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Mario Kleiner 0cbd0adc44 drm: Fix timestamp docs for variable refresh properties.
As discussed with Nicholas and Daniel Vetter (patchwork
link to discussion below), the VRR timestamping behaviour
produced utterly useless and bogus vblank/pageflip
timestamps. We have found a way to fix this and provide
sane behaviour.

As of Linux 5.2, the amdgpu driver will be able to
provide exactly the same vblank / pageflip timestamp
semantic in variable refresh rate mode as in standard
fixed refresh rate mode. This is achieved by deferring
core vblank handling (drm_crtc_handle_vblank()) until
the end of front porch, and also defer the sending of
pageflip completion events until end of front porch,
when we can safely compute correct pageflip/vblank
timestamps.

The same approach will be possible for other VRR
capable kms drivers, so we can actually have sane
and useful timestamps in VRR mode.

This patch removes the section of the docs that
describes the broken timestamp behaviour present
in Linux 5.0/5.1.

Fixes: ab7a664f7a ("drm: Document variable refresh properties")
Link: https://patchwork.freedesktop.org/patch/285333/
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190418060157.18968-1-mario.kleiner.de@gmail.com
Cc: stable@vger.kernel.org
2019-05-07 10:39:14 -05:00
arch Merge tag 'drm-intel-next-2019-04-17' of git://anongit.freedesktop.org/drm/drm-intel into drm-next 2019-04-24 10:02:20 +10:00
block block: do not leak memory in bio_copy_user_iov() 2019-04-10 16:14:40 -06:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto lib/lzo: separate lzo-rle from lzo 2019-03-07 18:32:03 -08:00
Documentation Merge tag 'drm-msm-next-2019-04-21' of https://gitlab.freedesktop.org/drm/msm into drm-next 2019-04-24 11:56:32 +10:00
drivers drm: Fix timestamp docs for variable refresh properties. 2019-05-07 10:39:14 -05:00
fs Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
include drm: increase drm mmap_range size to 1TB 2019-04-24 16:20:23 -05:00
init init/main: add checks for the return value of memblock_alloc*() 2019-03-12 10:04:02 -07:00
ipc Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
kernel Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
lib Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-04-09 16:20:59 -10:00
LICENSES LICENSES: Add GCC runtime library exception text 2019-01-16 14:54:15 -07:00
mm Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
net Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping" 2019-04-11 15:41:14 -04:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-11 08:54:01 -07:00
scripts fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock 2019-04-06 07:01:55 -10:00
security apparmor: Restore Y/N in /sys for apparmor's "enabled" 2019-04-10 04:24:48 -07:00
sound Linux 5.1-rc5 2019-04-15 15:51:49 +10:00
tools for-linus-20190412 2019-04-13 16:23:16 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt KVM/ARM fixes for 5.1 2019-03-28 19:07:30 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-04-12 12:49:54 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap Update Nicolas Pitre's email address 2019-04-02 18:12:44 -10:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS drm-misc-next for v5.2: 2019-04-24 10:12:50 +10:00
Makefile Linux 5.1-rc5 2019-04-14 15:17:41 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.