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Rodrigo Vivi 8edcda1266 drm/i915: Protect DDI port to DPLL map from theoretical race.
In case we have multiple modesets for different connectors
happening in parallel we could have a race on the RMW on these
shared registers.

This possibility was initially raised by Paulo when reviewing
commit '555e38d27317 ("drm/i915/cnl: DDI - PLL mapping")'
but the original possibility comes from commit '5416d871136d
("drm/i915/skl: Set the eDP link rate on DPLL0")'. Or maybe
later when atomic commits entered into picture.

Apparently the discussion around this topic showed that the
right solution would be on serializing the atomic commits in
a way that we don't have the possibility of races here since
if that parallel modeset happenings apparently many other
things will be on fire.

Code is there since SKL and there was no report of issue,
but since we never looked back to that serialization possibility,
and also we don't have an igt case for that it is better to at
least protect this corner.

Suggested-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Fixes: 555e38d273 ("drm/i915/cnl: DDI - PLL mapping")
Fixes: 5416d87113 ("drm/i915/skl: Set the eDP link rate on DPLL0")
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20171215224310.19103-1-rodrigo.vivi@intel.com
2017-12-18 14:38:26 -08:00
arch x86/gpu: add CFL to early quirks 2017-12-15 13:18:00 -08:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-01 08:05:45 -05:00
certs
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-11-28 16:22:10 -08:00
Documentation docs: fix, intel_guc_loader.c has been moved to intel_guc_fw.c 2017-12-12 16:24:05 +01:00
drivers drm/i915: Protect DDI port to DPLL map from theoretical race. 2017-12-18 14:38:26 -08:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs NFS client fixes for Linux 4.15-rc2 2017-12-01 20:04:20 -05:00
include x86/gpu: add CFL to early quirks 2017-12-15 13:18:00 -08:00
init EXPERT Kconfig menu: fix broken EXPERT menu 2017-11-17 16:10:05 -08:00
ipc Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
kernel Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-01 08:05:45 -05:00
lib RISC-V Cleanups and ABI Fixes for 4.15-rc2 2017-12-01 19:39:12 -05:00
mm Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-01 08:05:45 -05:00
net NFS client fixes for Linux 4.15-rc2 2017-12-01 20:04:20 -05:00
samples kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
scripts Merge branch 'akpm' (patches from Andrew) 2017-11-29 19:12:44 -08:00
security bug fixes: 2017-11-30 18:56:41 -05:00
sound Revert "ALSA: usb-audio: Fix potential zero-division at parsing FU" 2017-11-28 09:34:36 -08:00
tools Power management fixes for v4.15-rc2 2017-11-30 18:45:55 -05:00
usr
virt * x86 bugfixes: APIC, nested virtualization, IOAPIC 2017-11-30 08:15:19 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild misc updates for v4.15 2017-11-17 17:51:33 -08:00
.mailmap Add Jason Gunthorpe as co-maintainer of the RDMA stack 2017-11-17 09:36:18 -08:00
COPYING
CREDITS
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig
MAINTAINERS Merge arlied/drm-next into drm-misc-next 2017-12-04 16:04:45 -02:00
Makefile Linux 4.15-rc2 2017-12-03 11:01:47 -05:00
README

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.