Commit Graph

93 Commits

Author SHA1 Message Date
Wayne Boyer
666a45379e drm/i915: Separate cherryview from valleyview
The cherryview device shares many characteristics with the valleyview
device.  When support was added to the driver for cherryview, the
corresponding device info structure included .is_valleyview = 1.
This is not correct and leads to some confusion.

This patch changes .is_valleyview to .is_cherryview in the cherryview
device info structure and simplifies the IS_CHERRYVIEW macro.
Then where appropriate, instances of IS_VALLEYVIEW are replaced with
IS_VALLEYVIEW || IS_CHERRYVIEW or equivalent.

v2: Use IS_VALLEYVIEW || IS_CHERRYVIEW instead of defining a new macro.
    Also add followup patches to fix issues discovered during the first
    review. (Ville)
v3: Fix some style issues and one gen check. Remove CRT related changes
    as CRT is not supported on CHV. (Imre, Ville)
v4: Make a few more optimizations. (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Wayne Boyer <wayne.boyer@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449692975-14803-1-git-send-email-wayne.boyer@intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
2015-12-10 11:07:24 +01:00
Jani Nikula
bffce907d6 drm/i915: abstract i2c bit banging fallback in gmbus xfer
Choose between i2c bit banging and gmbus in a new higher level function,
and let the i2c core retry the first time we fall back to bit banging.

The i2c core imposes a timeout on -EAGAIN, but it defaults to 1 second,
and shouldn't be a problem for us.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448980166-23055-2-git-send-email-jani.nikula@intel.com
2015-12-02 13:29:41 +02:00
Jani Nikula
0aeb904888 drm/i915: simplify gmbus xfer error checks
Shorter, easier to follow code with no functional changes. In all cases,
the return value ultimately comes from gmbus_wait_hw_status() anyway.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448980166-23055-1-git-send-email-jani.nikula@intel.com
2015-12-02 13:27:46 +02:00
Ville Syrjälä
f0f59a00a1 drm/i915: Type safe register read/write
Make I915_READ and I915_WRITE more type safe by wrapping the register
offset in a struct. This should eliminate most of the fumbles we've had
with misplaced parens.

This only takes care of normal mmio registers. We could extend the idea
to other register types and define each with its own struct. That way
you wouldn't be able to accidentally pass the wrong thing to a specific
register access function.

The gpio_reg setup is probably the ugliest thing left. But I figure I'd
just leave it for now, and wait for some divine inspiration to strike
before making it nice.

As for the generated code, it's actually a bit better sometimes. Eg.
looking at i915_irq_handler(), we can see the following change:
  lea    0x70024(%rdx,%rax,1),%r9d
  mov    $0x1,%edx
- movslq %r9d,%r9
- mov    %r9,%rsi
- mov    %r9,-0x58(%rbp)
- callq  *0xd8(%rbx)
+ mov    %r9d,%esi
+ mov    %r9d,-0x48(%rbp)
 callq  *0xd8(%rbx)

So previously gcc thought the register offset might be signed and
decided to sign extend it, just in case. The rest appears to be
mostly just minor shuffling of instructions.

v2: i915_mmio_reg_{offset,equal,valid}() helpers added
    s/_REG/_MMIO/ in the register defines
    mo more switch statements left to worry about
    ring_emit stuff got sorted in a prep patch
    cmd parser, lrc context and w/a batch buildup also in prep patch
    vgpu stuff cleaned up and moved to a prep patch
    all other unrelated changes split out
v3: Rebased due to BXT DSI/BLC, MOCS, etc.
v4: Rebased due to churn, s/i915_mmio_reg_t/i915_reg_t/

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1447853606-2751-1-git-send-email-ville.syrjala@linux.intel.com
2015-11-18 15:39:11 +02:00
Ville Syrjälä
b2e8c6cd09 drm/i915: Streamline gpio_mmio_base deduction
If we ignore the BXT situation, we can observe that the only variables
affecting gpio_mmio_base is IS_VALLEVIEW and HAS_GMCH_DISPLAY. The BXT
situation we can fit into the same pattern if we change gmbus_pins_bxt[]
to house the GMCH GPIO register offsets (like we do for all other
platfotms). So let's do that.

We could even simplify the VLV situation more by including the
display_mmio_offset in the GPIO register defines, but let's leave it be
for now.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446672017-24497-13-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-11-18 14:35:00 +02:00
Ville Syrjälä
f0ab43e6c3 drm/i915: Introduce a gmbus power domain
Currently the gmbus code uses intel_aux_display_runtime_get/put in an
effort to make sure the hardware is powered up sufficiently for gmbus.
That function only takes the runtime PM reference which on VLV/CHV/BXT
is not enough. We need the disp2d/pipe-a well on VLV/CHV and power well
2 on BXT. So add a new power domnain for gmbus and kill off the now
unused intel_aux_display_runtime_get/put. And change
intel_hdmi_set_edid() to use the gmbus power domain too since that's all
we need there.

Also toss in a BUILD_BUG_ON() to catch problems if we run out of
bits for power domains. We're already really close to the limit...

[Patrik: Add gmbus string to debugfs output]

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447084107-8521-5-git-send-email-patrik.jakobsson@linux.intel.com
2015-11-17 20:55:18 +02:00
Rodrigo Vivi
ef11bdb3e0 drm/i915/kbl: Introduce Kabylake platform defition.
Kabylake is a Intel® Processor containing Intel® HD Graphics
following Skylake.

It is Gen9p5, so it inherits everything from Skylake.

Let's start by adding the platform separated from Skylake
but reusing most of all features, functions etc. Later we
rebase the PCI-ID patch without is_skylake=1
so we don't replace what original Author did there.

Few IS_SKYLAKEs if statements are not being covered by this patch
on purpose:
   - Workarounds: Kabylake is derivated from Skylake H0 so no
     		  W/As apply here.
   - GuC: A following patch removes Kabylake support with an
     	  explanation: No firmware available yet.
   - DMC/CSR: Done in a separated patch since we need to be carefull
     	      and load the version for revision 7 since
	      Kabylake is Skylake H0.

v2: relative cleaner commit message and added the missed
    IS_KABYLAKE to intel_i2c.c as pointed out by Jani.

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-10-28 21:35:38 +02:00
Ville Syrjälä
699fc401da drm/i915: Include gpio_mmio_base in GMBUS reg defines
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-13 13:16:09 +02:00
Linus Torvalds
099bfbfc7f Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
Pull drm updates from Dave Airlie:
 "This is the main drm pull request for v4.2.

  I've one other new driver from freescale on my radar, it's been posted
  and reviewed, I'd just like to get someone to give it a last look, so
  maybe I'll send it or maybe I'll leave it.

  There is no major nouveau changes in here, Ben was working on
  something big, and we agreed it was a bit late, there wasn't anything
  else he considered urgent to merge.

  There might be another msm pull for some bits that are waiting on
  arm-soc, I'll see how we time it.

  This touches some "of" stuff, acks are in place except for the fixes
  to the build in various configs,t hat I just applied.

  Summary:

  New drivers:
      - virtio-gpu:
                KMS only pieces of driver for virtio-gpu in qemu.
                This is just the first part of this driver, enough to run
                unaccelerated userspace on. As qemu merges more we'll start
                adding the 3D features for the virgl 3d work.
      - amdgpu:
                a new driver from AMD to driver their newer GPUs. (VI+)
                It contains a new cleaner userspace API, and is a clean
                break from radeon moving forward, that AMD are going to
                concentrate on. It also contains a set of register headers
                auto generated from AMD internal database.

  core:
      - atomic modesetting API completed, enabled by default now.
      - Add support for mode_id blob to atomic ioctl to complete interface.
      - bunch of Displayport MST fixes
      - lots of misc fixes.

  panel:
      - new simple panels
      - fix some long-standing build issues with bridge drivers

  radeon:
      - VCE1 support
      - add a GPU reset counter for userspace
      - lots of fixes.

  amdkfd:
      - H/W debugger support module
      - static user-mode queues
      - support killing all the waves when a process terminates
      - use standard DECLARE_BITMAP

  i915:
      - Add Broxton support
      - S3, rotation support for Skylake
      - RPS booting tuning
      - CPT modeset sequence fixes
      - ns2501 dither support
      - enable cmd parser on haswell
      - cdclk handling fixes
      - gen8 dynamic pte allocation
      - lots of atomic conversion work

  exynos:
      - Add atomic modesetting support
      - Add iommu support
      - Consolidate drm driver initialization
      - and MIC, DECON and MIPI-DSI support for exynos5433

  omapdrm:
      - atomic modesetting support (fixes lots of things in rewrite)

  tegra:
      - DP aux transaction fixes
      - iommu support fix

  msm:
      - adreno a306 support
      - various dsi bits
      - various 64-bit fixes
      - NV12MT support

  rcar-du:
      - atomic and misc fixes

  sti:
      - fix HDMI timing complaince

  tilcdc:
      - use drm component API to access tda998x driver
      - fix module unloading

  qxl:
      - stability fixes"

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (872 commits)
  drm/nouveau: Pause between setting gpu to D3hot and cutting the power
  drm/dp/mst: close deadlock in connector destruction.
  drm: Always enable atomic API
  drm/vgem: Set unique to "vgem"
  of: fix a build error to of_graph_get_endpoint_by_regs function
  drm/dp/mst: take lock around looking up the branch device on hpd irq
  drm/dp/mst: make sure mst_primary mstb is valid in work function
  of: add EXPORT_SYMBOL for of_graph_get_endpoint_by_regs
  ARM: dts: rename the clock of MIPI DSI 'pll_clk' to 'sclk_mipi'
  drm/atomic: Don't set crtc_state->enable manually
  drm/exynos: dsi: do not set TE GPIO direction by input
  drm/exynos: dsi: add support for MIC driver as a bridge
  drm/exynos: dsi: add support for Exynos5433
  drm/exynos: dsi: make use of array for clock access
  drm/exynos: dsi: make use of driver data for static values
  drm/exynos: dsi: add macros for register access
  drm/exynos: dsi: rename pll_clk to sclk_clk
  drm/exynos: mic: add MIC driver
  of: add helper for getting endpoint node of specific identifiers
  drm/exynos: add Exynos5433 decon driver
  ...
2015-06-26 13:18:51 -07:00
Jani Nikula
3f5f1554ee drm/i915: Fix DDC probe for passive adapters
Passive DP->DVI/HDMI dongles on DP++ ports show up to the system as HDMI
devices, as they do not have a sink device in them to respond to any AUX
traffic. When probing these dongles over the DDC, sometimes they will
NAK the first attempt even though the transaction is valid and they
support the DDC protocol. The retry loop inside of
drm_do_probe_ddc_edid() would normally catch this case and try the
transaction again, resulting in success.

That, however, was thwarted by the fix for [1]:

commit 9292f37e1f
Author: Eugeni Dodonov <eugeni.dodonov@intel.com>
Date:   Thu Jan 5 09:34:28 2012 -0200

    drm: give up on edid retries when i2c bus is not responding

This added code to exit immediately if the return code from the
i2c_transfer function was -ENXIO in order to reduce the amount of time
spent in waiting for unresponsive or disconnected devices. That was
possible because the underlying i2c bit banging algorithm had retries of
its own (which, of course, were part of the reason for the bug the
commit fixes).

Since its introduction in

commit f899fc64cd
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Jul 20 15:44:45 2010 -0700

    drm/i915: use GMBUS to manage i2c links

we've been flipping back and forth enabling the GMBUS transfers, but
we've settled since then. The GMBUS implementation does not do any
retries, however, bailing out of the drm_do_probe_ddc_edid() retry loop
on first encounter of -ENXIO. This, combined with Eugeni's commit, broke
the retry on -ENXIO.

Retry GMBUS once on -ENXIO on first message to mitigate the issues with
passive adapters.

This patch is based on the work, and commit message, by Todd Previte
<tprevite@gmail.com>.

[1] https://bugs.freedesktop.org/show_bug.cgi?id=41059

v2: Don't retry if using bit banging.

v3: Move retry within gmbux_xfer, retry only on first message.

v4: Initialize GMBUS0 on retry (Ville).

v5: Take index reads into account (Ville).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85924
Cc: Todd Previte <tprevite@gmail.com>
Cc: stable@vger.kernel.org
Tested-by: Oliver Grafe <oliver.grafe@ge.com> (v2)
Tested-by: Jim Bride <jim.bride@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-06-09 10:34:15 +03:00
Jani Nikula
6364e67e4a drm/i915: don't register invalid gmbus pins for skl
Do not expose invalid gmbus pins as i2c devices to userspace.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-05-20 11:25:50 +02:00
Jani Nikula
c1bad5b652 drm/i915: don't register invalid gmbus pins for bdw
Do not expose invalid gmbus pins as i2c devices to userspace.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-05-20 11:25:50 +02:00
Dave Airlie
e1dee1973c Merge tag 'drm-intel-next-2015-04-23-fixed' of git://anongit.freedesktop.org/drm-intel into drm-next
drm-intel-next-2015-04-23:
- dither support for ns2501 dvo (Thomas Richter)
- some polish for the gtt code and fixes to finally enable the cmd parser on hsw
- first pile of bxt stage 1 enabling (too many different people to list ...)
- more psr fixes from Rodrigo
- skl rotation support from Chandra
- more atomic work from Ander and Matt
- pile of cleanups and micro-ops for execlist from Chris
drm-intel-next-2015-04-10:
- cdclk handling cleanup and fixes from Ville
- more prep patches for olr removal from John Harrison
- gmbus pin naming rework from Jani (prep for bxt)
- remove ->new_config from Ander (more atomic conversion work)
- rps (boost) tuning and unification with byt/bsw from Chris
- cmd parser batch bool tuning from Chris
- gen8 dynamic pte allocation (Michel Thierry, based on work from Ben Widawsky)
- execlist tuning (not yet all of it) from Chris
- add drm_plane_from_index (Chandra)
- various small things all over

* tag 'drm-intel-next-2015-04-23-fixed' of git://anongit.freedesktop.org/drm-intel: (204 commits)
  drm/i915/gtt: Allocate va range only if vma is not bound
  drm/i915: Enable cmd parser to do secure batch promotion for aliasing ppgtt
  drm/i915: fix intel_prepare_ddi
  drm/i915: factor out ddi_get_encoder_port
  drm/i915/hdmi: check port in ibx_infoframe_enabled
  drm/i915/hdmi: fix vlv infoframe port check
  drm/i915: Silence compiler warning in dvo
  drm/i915: Update DRIVER_DATE to 20150423
  drm/i915: Enable dithering on NatSemi DVO2501 for Fujitsu S6010
  rm/i915: Move i915_get_ggtt_vma_pages into ggtt_bind_vma
  drm/i915: Don't try to outsmart gcc in i915_gem_gtt.c
  drm/i915: Unduplicate i915_ggtt_unbind/bind_vma
  drm/i915: Move ppgtt_bind/unbind around
  drm/i915: move i915_gem_restore_gtt_mappings around
  drm/i915: Fix up the vma aliasing ppgtt binding
  drm/i915: Remove misleading comment around bind_to_vm
  drm/i915: Don't use atomics for pg_dirty_rings
  drm/i915: Don't look at pg_dirty_rings for aliasing ppgtt
  drm/i915/skl: Support Y tiling in MMIO flips
  drm/i915: Fixup kerneldoc for struct intel_context
  ...

Conflicts:
	drivers/gpu/drm/i915/i915_drv.c
2015-05-08 20:51:06 +10:00
Dmitry Torokhov
9535c4757b drm/i915: cope with large i2c transfers
The hardware, according to the specs, is limited to 256 byte transfers,
and current driver has no protections in case users attempt to do larger
transfers. The code will just stomp over status register and mayhem
ensues.

Let's split larger transfers into digestable chunks. Doing this allows
Atmel MXT driver on Pixel 1 function properly (it hasn't since commit
9d8dc3e529 "Input: atmel_mxt_ts -
implement T44 message handling" which tries to consume multiple
touchscreen/touchpad reports in a single transaction).

Cc: stable@vger.kernel.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-04-23 23:48:18 +03:00
Jani Nikula
4c27283415 drm/i915: add bxt gmbus support
For BXT gmbus is pulled from PCH to CPU. From implementation point of
view only pin pair configuration will change. The existing
implementation supports all platforms previous to GEN8 and also SKL. But
for BXT pin pair configuration is completely different than SKL or other
previous GEN's. This patch introduces the new pin pair configuration
structure specific to BXT and also ensures every real gmbus port has a
gpio pin.

v3 by Jani: with the platform independent prep work in place, the bxt
enabling reduces to a fairly trivial patch. Credits are due Sunil for
giving me the ideas (with his patches) what the platform independent
parts should look like.

v4: Fix intel_hdmi_init_connector() for bxt. Abstract gmbus_pin access
more. s/GPU/PCH/ in commit message.

v5: Rebase.

Issue: VIZ-3574
Signed-off-by: A.Sunil Kamath <sunil.kamath@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-14 14:01:55 +02:00
Jani Nikula
88ac7939d2 drm/i915: base gmbus pin validity check on the gmbus pin map array
This will be helpful for adding future platforms. It is better to keep
the information in the single point of truth (the table) instead of
duplicating it into the validity function.

While at it, add dev_priv parameter to the function, also to prepare for
adding future platform support.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-01 14:11:56 +02:00
Jani Nikula
5ea6e5e36e drm/i915: index gmbus tables using the pin pair number
Index the gmbus tables directly using the pin instead of having a
confusing "port = i + 1" mapping. This finishes off removing the "gmbus
port" as a notion, and leaves us with just the "gmbus pin".

As pin 0 is invalid by definition and the gmbus tables will have a gap
at that index, add pin validity check to all the loops. This will be
benefitial for supporting platforms that have different numbers of pins,
or gaps.

v2: s/GMBUS_PIN_MAX/GMBUS_NUM_PINS/ (Ville, Daniel)

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-01 14:11:49 +02:00
Jani Nikula
0184df465e drm/i915: refer to pin instead of port in the intel_i2c.c interfaces
Rename intel_gmbus_is_port_valid to intel_gmbus_is_valid_pin, and rename
port parameters to pin as well. This matches usage all around, as
usually a pin is passed to the validity check function. No functional
changes.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-01 14:11:38 +02:00
Ville Syrjälä
f8bf63fdcb drm/i915: Kill duplicated cdclk readout code from i2c
We have a slightly different way of readoing out the cdclk in
gmbus_set_freq(). Kill that and just call .get_display_clock_speed().

Also need to remove the GMBUSFREQ update from intel_i2c_reset() since
that gets called way too early. Let's do it in intel_modeset_init_hw()
instead, and also pull the initial vlv_cdclk_freq update there from
init_clock gating.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-07-07 11:27:52 +02:00
Ville Syrjälä
dfcab17e57 drm/i915: Change vlv cdclk to use kHz units
Use kHz units in vlv cdclk code since that's more customary.

Also replace the precomputed 90% values with *9/10 computation
for extra clarity.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-07-07 11:14:53 +02:00
Daniel Vetter
4e6b788c3f drm/i915: Disable dp aux irq on g4x
Apparently it's broken in the exact same way as the gmbus irq. For
reference of the full story see

commit c12aba5aa0
Author: Jiri Kosina <jkosina@suse.cz>
Date:   Tue Mar 19 09:56:57 2013 +0100

    drm/i915: stop using GMBUS IRQs on Gen4 chips

The effect is that we have a storm of unclaimed interrupts on the
legacy irq line. If that one is used by a different device then the
kernel will complain and rather quickly kill the irq source. Which
breaks any device trying to actually use the legacy irq line.

This regression has been introduced

commit 4aeebd7443
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Oct 31 09:53:36 2013 +0100

    drm/i915: dp aux irq support for g4x/vlv

Note that disabling MSI works around the issue, but we can't do that
since apparently then the hw will miss interrupts. At least if
relevant comments in i915_irq.c are accurate.

v2: Cross-reference dp aux and gmbus gen4 comments.

v3: Consolidate harder into i915_drv.h as suggested by Chris.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-02-07 16:40:07 +01:00
Jesse Barnes
586f49dc78 drm/i915/vlv: split CCK and DDR freq usage
It's possible that the CCK clock could run at a different rate than the
DDR clock, so use the same method to get CCK as the GMBUS code does when
calculating the new CDclk divider in the VLV display code.

Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-11-05 19:28:47 +01:00
Jesse Barnes
30a970c6a6 drm/i915/vlv: modeset_global_* for VLV v7
On VLV/BYT, we can adjust the CDclk frequency up or down based on the
max pixel clock we need to drive.  Lowering it can save power, while
raising it is necessary to support high resolution.

Add a new callback in modeset_affected_pipes and a
modeset_global_resources function to perform this adjustment as
necessary.

v2: use punit interface for 320 and 266 MHz CDclk adjustments (Ville)
v3: reset GMBUS dividers too, since we changed CDclk (Ville)
v4: jump to highest voltage when going to 400MHz CDclk (Jesse)
v5: drop duplicate define (Ville)
    use shifts by 1 for fixed point (Ville)
    drop new callback (Daniel)
v6: fixup adjusted_mode.clock -> adjusted_mode.crtc_clock again (Ville)
    document Bunit reg access better (Ville)
v7: pass modeset_pipes and pipe_config to global_pipes so we get the right
    clock data (Ville)

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-11-05 19:28:18 +01:00
Chon Ming Lee
24eb2d599b drm/i915: Program GMBUS Frequency based on the CDCLK for VLV.
CDCLK is used to generate the gmbus clock.  This is normally done by
BIOS. Program the value if the BIOS-less system doesn't do it.

v2: Move this to intel_i2c_reset to allow reprogram the gmbus frequency
during resume. (Daniel)

v3: Change GMBUS_FREQ to GMBUSFREQ_VLV, and use VLV_DISPLAY_BASE.
(Ville).
	Remove cdclk_ratio[] table, and calculate the cdclk ratio instead.
(Ville).
 	Change the shift then mask for reg read, to mask first, then shift.
(Ville).
	Remove the gmbus frequency calculation = cdclk/1.01.  Based on BIOS
programming, gmbus frequency = cdclk frequency. (Ville)
	Add get_disp_clk_div, which can use to get cdclk/czclk divide.

v4: Fix the mmio_offset base for CZCLK_CDCLK_FREQ_RATIO, gmbus_freq
calculation, and duplicate check for gmbus_freq. (Ville)

In VLV, the spec is wrong about 4Mhz reference frequency for GMBUS. It
should be 1Mhz.

Signed-off-by: Chon Ming Lee <chon.ming.lee@intel.com>
[danvet: Add the comment Ville suggested. Also appease checkpatch a
bit.]
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-10-01 07:45:41 +02:00
Paulo Zanoni
c67a470b1d drm/i915: allow package C8+ states on Haswell (disabled)
This patch allows PC8+ states on Haswell. These states can only be
reached when all the display outputs are disabled, and they allow some
more power savings.

The fact that the graphics device is allowing PC8+ doesn't mean that
the machine will actually enter PC8+: all the other devices also need
to allow PC8+.

For now this option is disabled by default. You need i915.allow_pc8=1
if you want it.

This patch adds a big comment inside i915_drv.h explaining how it
works and how it tracks things. Read it.

v2: (this is not really v2, many previous versions were already sent,
     but they had different names)
    - Use the new functions to enable/disable GTIMR and GEN6_PMIMR
    - Rename almost all variables and functions to names suggested by
      Chris
    - More WARNs on the IRQ handling code
    - Also disable PC8 when there's GPU work to do (thanks to Ben for
      the help on this), so apps can run caster
    - Enable PC8 on a delayed work function that is delayed for 5
      seconds. This makes sure we only enable PC8+ if we're really
      idle
    - Make sure we're not in PC8+ when suspending
v3: - WARN if IRQs are disabled on __wait_seqno
    - Replace some DRM_ERRORs with WARNs
    - Fix calls to restore GT and PM interrupts
    - Use intel_mark_busy instead of intel_ring_advance to disable PC8
v4: - Use the force_wake, Luke!
v5: - Remove the "IIR is not zero" WARNs
    - Move the force_wake chunk to its own patch
    - Only restore what's missing from RC6, not everything

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-08-23 14:52:33 +02:00
Imre Deak
3598706b52 drm/i915: avoid premature DP AUX timeouts
During DP AUX communication we might time out 1 jiffy too early, because
the calculated expiry jiffy value is one less than needed.

This is only one reason for false DP AUX timeouts. For a complete
solution we also need the following fix, which is now queued for
mainline: http://marc.info/?l=linux-kernel&m=136748515710837&w=2

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=64133

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-05-22 13:51:26 +02:00
Imre Deak
2554fc1fa6 drm/i915: use msecs_to_jiffies_timeout instead of open coding the same
Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-05-22 13:51:20 +02:00
Ben Widawsky
ab5c608b2d drm/i915: Don't touch South Display when PCH_NOP
Interrupts, clock gating, LVDS, and GMBUS are all within the, "this will
be bad for CPU" range when we have PCH_NOP.

There is a bit of a hack in init clock gating. We want to do most of the
clock gating, but the part we skip will hang the system. It could
probably be abstracted a bit better, but I don't feel it's too
unsightly.

v2: Use inverse HAS_PCH_NOP check (Jani)

v3: Actually do what I claimed in v2 (spotted by Daniel)
Merge Ivybridge IRQ handler PCH check to decrease whitespace (Daniel)
Move LVDS bail into this patch (Ben)

v4: logical rebase conflict resolution with SDEIIR (Ben)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>

Brush up patch a bit and resolve conflicts:
- Adjust PCH_NOP checks due to Egbert's hpd handling rework.
- Addd a PCH_NOP check in the irq uninstall code.
- Resolve conflicts with Paulo's SDE irq handling race fix.

v5: Drop the added hunks in the ilk irq handler again, they're bogus.
OOps.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-04-08 20:53:00 +02:00
Jiri Kosina
c12aba5aa0 drm/i915: stop using GMBUS IRQs on Gen4 chips
Commit 28c70f162 ("drm/i915: use the gmbus irq for waits") switched to
using GMBUS irqs instead of GPIO bit-banging for chipset generations 4
and above.

It turns out though that on many systems this leads to spurious interrupts
being generated, long after the register write to disable the IRQs has been
issued.

Typically this results in the spurious interrupt source getting
disabled:

[    9.636345] irq 16: nobody cared (try booting with the "irqpoll" option)
[    9.637915] Pid: 4157, comm: ifup Tainted: GF            3.9.0-rc2-00341-g0863702 #422
[    9.639484] Call Trace:
[    9.640731]  <IRQ>  [<ffffffff8109b40d>] __report_bad_irq+0x1d/0xc7
[    9.640731]  [<ffffffff8109b7db>] note_interrupt+0x15b/0x1e8
[    9.640731]  [<ffffffff810999f7>] handle_irq_event_percpu+0x1bf/0x214
[    9.640731]  [<ffffffff81099a88>] handle_irq_event+0x3c/0x5c
[    9.640731]  [<ffffffff8109c139>] handle_fasteoi_irq+0x7a/0xb0
[    9.640731]  [<ffffffff8100400e>] handle_irq+0x1a/0x24
[    9.640731]  [<ffffffff81003d17>] do_IRQ+0x48/0xaf
[    9.640731]  [<ffffffff8142f1ea>] common_interrupt+0x6a/0x6a
[    9.640731]  <EOI>  [<ffffffff8142f952>] ? system_call_fastpath+0x16/0x1b
[    9.640731] handlers:
[    9.640731] [<ffffffffa000d771>] usb_hcd_irq [usbcore]
[    9.640731] [<ffffffffa0306189>] yenta_interrupt [yenta_socket]
[    9.640731] Disabling IRQ #16

The really curious thing is now that irq 16 is _not_ the interrupt for
the i915 driver when using MSI, but it _is_ the interrupt when not
using MSI. So by all indications it seems like gmbus is able to
generate a legacy (shared) interrupt in MSI mode on some
configurations. I've tried to reproduce this and the differentiating
thing seems to be that on unaffected systems no other device uses irq
16 (which seems to be the non-MSI intel gfx interrupt on all gm45).

I have no idea how that even can happen.

To avoid tempting this elephant into a rage, just disable gmbus
interrupt support on gen 4.

v2: Improve the commit message with exact details of what's going on.
Also add a comment in the code to warn against this particular
elephant in the room.

v3: Move the comment explaing how gen4 blows up next to the definition
of HAS_GMBUS_IRQ to keep the code-flow straight. Suggested by Chris
Wilson.

Signed-off-by: Jiri Kosina <jkosina@suse.cz> (v1)
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
References: https://lkml.org/lkml/2013/3/8/325
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-03-20 00:03:16 +01:00
Ville Syrjälä
d811215004 drm/i915: GPIO/GMBUS registers need an offset on VLV
GPIO/GMBUS registers must be offset on VLV, so simply
adjust gpio_mmio_base to include the correct offset.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-01-24 23:45:03 +01:00
Daniel Vetter
ef04f00d12 drm/i915: use _NOTRACE for gmbus/dp aux wait loops
Less clutter in the traces. And in both cases we yell rather loud
into the logs if we time out. Patch suggested by Chris Wilson.

v2: Annotate another I915_READ in dp_aux to be consistent - we filter
out all register io in wait_for and similar loops. Chris also
suggested to mark all dp_aux register access as _NOTRACE, but I think
we should keep all functionally relevant access around, and filter
unneeded bits in userspace after the trace is captured.

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-12-06 13:19:13 +01:00
Daniel Vetter
2c438c0273 drm/i915: use gmbus irq to wait for gmbus idle
GMBUS_ACTIVE has inverted sense and so doesn't fit into the
wait_hw_status helper, hence create a new gmbus_wait_idle functions.
Also, we only care about the idle irq event and nothing else, which
allows us to use the wait_event_timeout helper directly without
jumping through hoops to catch NAKs.

Since gen2/3 don't have gmbus interrupts, handle them separately with
the old wait_for macro.

This shaves another few ms off reading EDID from a hdmi screen on my
testbox here. EDID reading with interrupt driven gmbus is now as fast
as with busy-looping gmbus at 28 ms here (with negligible cpu
overhead).

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-12-06 13:14:38 +01:00
Daniel Vetter
28c70f162a drm/i915: use the gmbus irq for waits
We need two special things to properly wire this up:
- Add another argument to gmbus_wait_hw_status to pass in the
  correct interrupt bit in gmbus4.
- Since we can only get an irq for one of the two events we want,
  hand-roll the wait_event_timeout code so that we wake up every
  jiffie and can check for NAKs. This way we also subsume gmbus
  support for platforms without interrupts (or where those are not
  yet enabled).

The important bit really is to only enable one gmbus interrupt source
at the same time - with that piece of lore figured out, this seems to
work flawlessly.

Ben Widawsky rightfully complained the lack of measurements for the
claimed benefits (especially since the first version was actually
broken and fell back to bit-banging). Previously reading the 256 byte
hdmi EDID takes about 72 ms here. With this patch it's down to 33 ms.
Given that transfering the 256 bytes over i2c at wire speed takes
20.5ms alone, the reduction in additional overhead is rather nice.

v2: Chris Wilson wondered whether GMBUS4 might contain some set bits
when booting up an hence result in some spurious interrupts. Since we
clear GMBUS4 after every wait and we do gmbus transfer really early in
the setup sequence to detect displays the window is small, but still
be paranoid and clear it properly.

v3: Clarify the comment that gmbus irq generation can only support one
kind of event, why it bothers us and how we work around that limit.

Cc: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-12-06 13:14:37 +01:00
Daniel Vetter
61168c53f5 drm/i915: extract gmbus_wait_hw_status
The gmbus interrupt generation is rather fiddly: We can only ever
enable one interrupt source (but we always want to check for NAK
in addition to the real bit). And the bits in the gmbus status
register don't map at all to the bis in the irq register.

To prepare for this mess, start by extracting the hw status wait
loop into it's own function, consolidate the NAK error handling a
bit. To keep things flexible, pass in the status bit we care about
(in addition to any NAK signalling).

v2: I've failed to notice that the sense of GMBUS_ACTIVE is inverted,
Chris Wilson gladly pointed that out for me. To keep things simple,
ignore that case for  now (we only need to idle the gmbus controller
at the end of an entire i2c transaction, not after every message).

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-12-06 13:14:36 +01:00
Chris Wilson
f2ce9fafc1 drm/i915/i2c: Track users of GMBUS force-bit
This fixes a regression for SDVO from

commit fbfcc4f3a0
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Mon Oct 22 16:12:18 2012 +0300

    drm/i915/sdvo: restore i2c adapter config on intel_sdvo_init() failures

As SDVOB and SDVOC are multiplexed on the same pin, if a chipset does
not have the second SDVO encoder, it will then remove the force-bit
setting on the common i2c adapter during teardown. All subsequent
attempts of trying to use GMBUS with SDVOB then fail.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
[danvet: fixup inversion in the debug printout, noticed by Jani
Nikulai.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-11-13 16:10:04 +01:00
David Howells
760285e7e7 UAPI: (Scripted) Convert #include "..." to #include <path/...> in drivers/gpu/
Convert #include "..." to #include <path/...> in drivers/gpu/.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
2012-10-02 18:01:07 +01:00
David Howells
4126d5d61f UAPI: (Scripted) Remove redundant DRM UAPI header #inclusions from drivers/gpu/.
Remove redundant DRM UAPI header #inclusions from drivers/gpu/.

Remove redundant #inclusions of core DRM UAPI headers (drm.h, drm_mode.h and
drm_sarea.h).  They are now #included via drmP.h and drm_crtc.h via a preceding
patch.

Without this patch and the patch to make include the UAPI headers from the core
headers, after the UAPI split, the DRM C sources cannot find these UAPI headers
because the DRM code relies on specific -I flags to make #include "..."  work
on headers in include/drm/ - but that does not work after the UAPI split without
adding more -I flags.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
2012-10-02 18:01:05 +01:00
Jani Nikula
cee25168e9 drm/i915: ensure i2c adapter is all set before adding it
i2c_add_adapter() may do i2c transfers on the bus to detect supported
devices. Therefore the adapter needs to be all set before adding it. This
was not the case for the bit-banging fallback, resulting in an oops if the
device detection GMBUS transfers timed out. Fix the issue by calling
i2c_add_adapter() only after intel_gpio_setup().

LKML-Reference: <5021F00B.7000503@ionic.de>
Tested-by: Mihai Moldovan <ionic@ionic.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-08-13 19:04:24 +02:00
Alan Cox
9978cf5042 i915: Remove silly test
drv_priv->gmbus is an array. Comparing it with NULL is somewhat less useful
than a chocolate teapot.

Possibly we should be testing bus != NULL each iteration of the loop
instead ?

gcc could help by warning too!

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-07-26 09:50:35 +02:00
Daniel Vetter
65e8186602 drm/i915: be more careful when returning -ENXIO in gmbus transfer
... flaky ddc hardware can cause a spurious NAK, resulting in the i2c
core and drm edid functions not trying to retry the edid transfer.

Luckily the gmbus quiescenting also times out for these cases, so we
can get out of this mess by returning -ETIMEDOUT for this specific
case. This way we keep the fast-fail of returning -ENXIO if there is
no device present, speeding up the boot process.

This regression has been introduced in

commit e646d57735
Author: Daniel Kurtz <djkurtz@chromium.org>
Date:   Fri Mar 30 19:46:38 2012 +0800

    drm/i915/intel_i2c: always wait for IDLE before clearing NAK

v2: Return -ETIMEDOUT for this case and keep the -ENXIO for real NAKs,
suggested by Daniel Kurtz.

Cc: Daniel Kurtz <djkurtz@chromium.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49518
Reported-and-Tested-by: Julian Simioni <julian.simioni@gmail.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-05-21 21:04:21 +02:00
Daniel Vetter
83ee9e6458 drm/i915: disable gmbus on i830
The hw just returns garbage.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49838
Reported-and-tested-by: Vladyslav <DFEW.Entwickler@googlemail.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-05-19 22:39:55 +02:00
Daniel Kurtz
56fa6d6ff7 drm/i915/intel_i2c: reduce verbosity of some messages
Some of these messages can be hit when userspace tries to probe the i2c
with nothing connected or if the driver code tries to do the same.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=48248
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-13 15:03:00 +02:00
Daniel Kurtz
79985eee84 drm/i915/intel_i2c: handle zero-length reads
A common method of probing an i2c bus is trying to do a zero-length read.
Handle this case by checking the length first waiting for data to be read.

This is actually important, since attempting a zero-length read is one
of the ways that i2cdetect and i2c_new_probed_device detect whether
there is device present on the bus with a given address.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=48269
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-13 15:02:52 +02:00
Daniel Kurtz
e2ba4fb313 drm/i915/intel_i2c: remove POSTING_READ() from gmbus transfers
The POSTING_READ() calls were originally added to make sure the writes
were flushed before any timing delays and across loops.
Now that the code has settled a bit, let's remove them.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-12 21:14:08 +02:00
Daniel Kurtz
90e6b26d6b drm/i915/intel_i2c: reuse GMBUS2 value read in polling loop
Save the GMBUS2 value read while polling for state changes, and then
reuse this value when determining for which reason the loops were exited.
This is a small optimization which saves a couple of bus accesses for
memory mapped IO registers.

To avoid "assigning in if clause" checkpatch errors", use a ret variable
to store the wait_for macro return value.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-12 21:14:08 +02:00
Daniel Kurtz
56f9eac054 drm/i915/intel_i2c: use INDEX cycles for i2c read transactions
It is very common for an i2c device to require a small 1 or 2 byte write
followed by a read.  For example, when reading from an i2c EEPROM it is
common to write and address, offset or index followed by a reading some
values.

The i915 gmbus controller provides a special "INDEX" cycle for performing
such a small write followed by a read.  The INDEX can be either one or two
bytes long.  The advantage of using such a cycle is that the CPU has
slightly less work to do once the read with INDEX cycle is started.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-12 21:14:07 +02:00
Daniel Kurtz
72d66afd14 drm/i915/intel_i2c: use WAIT cycle, not STOP
The i915 is only able to generate a STOP cycle (i.e. finalize an i2c
transaction) during a DATA or WAIT phase.  In other words, the
controller rejects a STOP requested as part of the first transaction in a
sequence.

Thus, for the first transaction we must always use a WAIT cycle, detect
when the device has finished (and is in a WAIT phase), and then either
start the next transaction, or, if there are no more transactions,
generate a STOP cycle.

Note: Theoretically, the last transaction of a multi-transaction sequence
could initiate a STOP cycle.  However, this slight optimization is left
for another patch.  We return -ETIMEDOUT if the hardware doesn't
deactivate after the STOP cycle.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
[danvet: added comment to the code that gmbus can't generate STOP on
the very first cycle.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-12 21:14:07 +02:00
Daniel Kurtz
e646d57735 drm/i915/intel_i2c: always wait for IDLE before clearing NAK
The GMBUS controller can report a NAK condition while a transaction is
still active. If the driver is fast enough, and the bus is slow enough,
the driver may clear the NAK condition while the controller is still
busy, resulting in a confused GMBUS controller.  This will leave the
controller in a bad state such that the next transaction may fail.

Also, return -ENXIO if a device NAKs a transaction.

Note: this patch also refactors gmbus_xfer to remove the "done" label.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-12 21:14:07 +02:00
Daniel Kurtz
7a39a9d476 drm/i915/intel_i2c: use double-buffered writes
The GMBUS controller GMBUS3 register is double-buffered.  Take advantage
of this  by writing two 4-byte words before the first wait for HW_RDY.
This helps keep the GMBUS controller from becoming idle during long writes.

In fact, during experiments using the GMBUS interrupts, the HW_RDY
interrupt would only trigger for transactions >4 bytes after 2 writes
to GMBUS3.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-12 21:14:06 +02:00
Daniel Kurtz
26883c31b0 drm/i915/intel_i2c: handle zero-length writes
A common method of probing an i2c bus is trying to do a zero-length write.
Handle this case by checking the length first before decrementing it.

This is actually important, since attempting a zero-length write is one
of the ways that i2cdetect and i2c_new_probed_device detect whether
there is device present on the bus with a given address.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-04-12 21:14:06 +02:00