linux/drivers/gpu/drm
Paulo Zanoni 1a5ef5b7b4 drm/i915: don't wait for power cycle when waiting for power off
Function ironlake_wait_panel_off should just wait for the power off
delay, while function ironlake_wait_panel_power_cycle should wait for
the panel cycle (that's required after we turn the panel off, before
we enable it again).

The problem is that, currently, ironlake_wait_panel_off is waiting not
just for the panel to be off, but also for the power cycle delay and
the backlight off delay. This function relies on the PP_STATUS bits
3:0, which are not documented and not supposed to be used. A quick
analysis of the values we get while waiting quickly shows that power
off is reached while bits 3:0 are still 0x1, and the time it takes to
become 0x0 is the power cycle delay.

On my system with backlight off delay of 200ms, power down delay of
50ms and power cycle delay of 500ms, this is what I get:
 - Start waiting with value 0x80000008, timestamp 6.429364.
 - Jumps to 0xa0000003, timestamp 6.431360 (time waited: 0.001996)
 - Jumps to 0xa0000002, timestamp 6.631277 (time waited: 0.201913)
 - Jumps to 0x08000001, timestamp 6.681258 (time waited: 0.251894)
 - Jumps to 0x00000000, timestamp 7.192012 (time waited: 0.762648)

As you can see, ironlake_wait_panel_off is sleeping 760ms instead of
the expected 50ms: the first 200ms matches the backlight off delay
(which we should already have waited for!), then the 50ms for the real
panel off delay, then the 500ms for the panel power cycle.

This patch makes is look just at bits 31 and 29:28, which will ignore
the panel power cycle.

And just to be clear: this saves 500ms on my system every time we
disable the panel. But we can still save 200ms more (the backlight off
delay) on the next patches.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuougseek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-24 17:22:48 +01:00
..
armada Merge branch 'drm-intel-next' of git://people.freedesktop.org/~danvet/drm-intel into drm-next 2014-01-20 10:21:54 +10:00
ast drivers: gpu: Mark functions as static in ast_ttm.c 2014-01-14 12:59:16 +10:00
bochs drm/bochs: new driver 2013-12-23 11:02:39 +10:00
cirrus drivers: gpu: Mark functions as static and remove unused function in cirrus_ttm.c 2014-01-14 12:59:19 +10:00
exynos drm/exynos: fix build error caused by removed drm core macros 2014-01-07 16:53:25 +09:00
gma500 drm/gma500: Remove unused function declaration 2014-01-14 12:38:40 +10:00
i2c drm/i2c: tda998x: set VIF for full range, underscanned display 2013-10-18 15:58:32 +01:00
i810 drm: kill DRIVER_REQUIRE_AGP 2013-12-18 11:17:53 +10:00
i915 drm/i915: don't wait for power cycle when waiting for power off 2014-01-24 17:22:48 +01:00
mga drivers: gpu: Include appropriate header file in mga_ioc32.c 2014-01-14 12:59:24 +10:00
mgag200 drm/mgag200: fix oops in cursor code. 2014-01-16 14:43:04 +10:00
msm drm: store the gem vma offset manager in a typed pointer 2014-01-14 12:38:32 +10:00
nouveau Merge branch 'drm-intel-next' of git://people.freedesktop.org/~danvet/drm-intel into drm-next 2014-01-20 10:21:54 +10:00
omapdrm drm: store the gem vma offset manager in a typed pointer 2014-01-14 12:38:32 +10:00
panel drm/panel: Add support for Panasonic VVX10F004B0 2013-12-17 18:09:58 +01:00
qxl gpu: fix qxl missing crc32_le 2014-01-14 13:08:37 +10:00
r128 drivers: gpu: Include appropriate header file in r128_ioc32.c 2014-01-14 13:05:37 +10:00
radeon Merge branch 'drm-vbl-timestamp' of git://gitorious.org/vsyrjala/linux into drm-next 2014-01-22 09:13:13 +10:00
rcar-du Merge branch 'drm/next/du' of git://linuxtv.org/pinchartl/fbdev into drm-next 2013-12-23 10:42:36 +10:00
savage drm: Kill DRM_*MEMORYBARRIER 2013-12-18 11:35:21 +10:00
shmobile drm/shmob: call drm_put_dev directly from ->remove hook 2013-12-18 11:05:46 +10:00
sis drivers: gpu: Mark function as static in sis_drv.c 2014-01-14 13:04:33 +10:00
tdfx
tegra drm/tegra: Changes for v3.14-rc1 2013-12-23 10:43:42 +10:00
tilcdc drm: store the gem vma offset manager in a typed pointer 2014-01-14 12:38:32 +10:00
ttm Merge branch 'drm-intel-next' of git://people.freedesktop.org/~danvet/drm-intel into drm-next 2014-01-20 10:21:54 +10:00
udl drm: Push dirtyfb ioctl kms locking down to drivers 2013-12-18 10:49:08 +10:00
via drivers: gpu: Mark function as static in via_drv.c 2014-01-14 13:05:00 +10:00
vmwgfx drm/vmwgfx: Fix recently introduced sparse / smatch warnings and errors 2014-01-21 13:22:18 +01:00
ati_pcigart.c
drm_agpsupport.c drm: rip out DRM_AGP_MEM and DRM_AGP_KERN 2013-12-18 11:32:55 +10:00
drm_auth.c
drm_buffer.c drm: Kill DRM_COPY_(TO|FROM)_USER 2013-12-18 11:35:01 +10:00
drm_bufs.c drm: rip out drm_core_has_AGP 2013-12-18 11:20:04 +10:00
drm_cache.c
drm_context.c
drm_crtc_helper.c drm: Pass the display mode to drm_calc_timestamping_constants() 2014-01-20 11:04:46 +02:00
drm_crtc.c drm: Push dirtyfb ioctl kms locking down to drivers 2013-12-18 10:49:08 +10:00
drm_debugfs.c drm: Make drm_debugfs_list const 2013-11-06 12:05:21 +10:00
drm_dma.c
drm_dp_helper.c
drm_drv.c drm: Kill file_priv->ioctl_count tracking 2013-12-18 11:42:13 +10:00
drm_edid_load.c drm/edid: Make edid_load() return a void * 2013-12-18 10:42:13 +10:00
drm_edid.c drm/edid: Populate picture aspect ratio for CEA modes 2014-01-20 18:32:21 +01:00
drm_encoder_slave.c
drm_fb_cma_helper.c
drm_fb_helper.c drm: do not steal the display if we have a master 2013-12-18 10:47:20 +10:00
drm_flip_work.c kfifo API type safety 2013-11-15 09:32:23 +09:00
drm_fops.c drm: remove dev->vma_count 2013-12-18 11:43:29 +10:00
drm_gem_cma_helper.c
drm_gem.c drm/gem: Always initialize the gem object in object_init 2014-01-21 10:19:58 +01:00
drm_global.c
drm_hashtab.c
drm_info.c drm: remove dev->vma_count 2013-12-18 11:43:29 +10:00
drm_ioc32.c
drm_ioctl.c
drm_irq.c drm/radeon: Move the early vblank IRQ fixup to radeon_get_crtc_scanoutpos() 2014-01-20 12:21:35 +02:00
drm_lock.c
drm_memory.c drm: rip out DRM_AGP_MEM and DRM_AGP_KERN 2013-12-18 11:32:55 +10:00
drm_mipi_dsi.c drm: Add MIPI DSI bus support 2013-12-17 18:09:43 +01:00
drm_mm.c
drm_modes.c Revert "drm: copy mode type in drm_mode_connector_list_update()" 2014-01-14 12:50:49 +10:00
drm_panel.c drm: Add panel support 2013-12-17 18:09:46 +01:00
drm_pci.c drm: remove global_mutex locking around agp_init 2013-12-18 11:27:29 +10:00
drm_platform.c drm: restrict the device list for shadow attached drivers 2013-12-18 11:08:36 +10:00
drm_prime.c
drm_rect.c
drm_scatter.c
drm_stub.c Merge branch 'drm-intel-next' of git://people.freedesktop.org/~danvet/drm-intel into drm-next 2014-01-20 10:21:54 +10:00
drm_sysfs.c drm/sysfs: fix OOM verification 2013-11-28 14:35:23 +10:00
drm_trace_points.c
drm_trace.h
drm_usb.c drivers: gpu: Include appropriate header file in drm_usb.c 2014-01-14 12:53:41 +10:00
drm_vm.c drm: remove dev->vma_count 2013-12-18 11:43:29 +10:00
drm_vma_manager.c
Kconfig drm/bochs: new driver 2013-12-23 11:02:39 +10:00
Makefile drm/bochs: new driver 2013-12-23 11:02:39 +10:00
README.drm

************************************************************
* For the very latest on DRI development, please see:      *
*     http://dri.freedesktop.org/                          *
************************************************************

The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).

The DRM supports the Direct Rendering Infrastructure (DRI) in four major
ways:

    1. The DRM provides synchronized access to the graphics hardware via
       the use of an optimized two-tiered lock.

    2. The DRM enforces the DRI security policy for access to the graphics
       hardware by only allowing authenticated X11 clients access to
       restricted regions of memory.

    3. The DRM provides a generic DMA engine, complete with multiple
       queues and the ability to detect the need for an OpenGL context
       switch.

    4. The DRM is extensible via the use of small device-specific modules
       that rely extensively on the API exported by the DRM module.


Documentation on the DRI is available from:
    http://dri.freedesktop.org/wiki/Documentation
    http://sourceforge.net/project/showfiles.php?group_id=387
    http://dri.sourceforge.net/doc/

For specific information about kernel-level support, see:

    The Direct Rendering Manager, Kernel Support for the Direct Rendering
    Infrastructure
    http://dri.sourceforge.net/doc/drm_low_level.html

    Hardware Locking for the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/hardware_locking_low_level.html

    A Security Analysis of the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/security_low_level.html