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Aurabindo Pillai d2aa135683 drm/amd/display: take dc_lock in short pulse handler only
[Why]
Conditions that end up modifying the global dc state must be locked.
However, during mst allocate payload sequence, lock is already taken.
With StarTech 1.2 DP hub, we get an HPD RX interrupt for a reason other
than to indicate down reply availability right after sending payload
allocation. The handler again takes dc lock before calling the
dc's HPD RX handler. Due to this contention, the DRM thread which waits
for MST down reply never gets a chance to finish its waiting
successfully and ends up timing out. Once the lock is released, the hpd
rx handler fires and goes ahead to read from the MST HUB, but now its
too late and the HUB doesnt lightup all displays since DRM lacks error
handling when payload allocation fails.

[How]
Take lock only if there is a change in link status or if automated test
pattern bit is set. The latter fixes the null pointer dereference when
running certain DP Link Layer Compliance test.

Fixes: c8ea79a8a2 ("drm/amd/display: NULL pointer error during compliance test")

Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2021-05-21 10:30:26 -04:00
arch Core Changes: 2021-05-21 08:55:23 +10:00
block block-5.13-2021-05-14 2021-05-15 08:52:30 -07:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto for-5.13/drivers-2021-04-27 2021-04-28 14:39:37 -07:00
Documentation drm-misc-next for 5.14: 2021-05-20 13:31:12 +10:00
drivers drm/amd/display: take dc_lock in short pulse handler only 2021-05-21 10:30:26 -04:00
fs Merge branch 'akpm' (patches from Andrew) 2021-05-15 09:42:27 -07:00
include Merge tag 'amd-drm-next-5.14-2021-05-21' of https://gitlab.freedesktop.org/agd5f/linux into drm-next 2021-05-21 15:59:05 +10:00
init Merge branch 'akpm' (patches from Andrew) 2021-05-07 00:34:51 -07:00
ipc ipc/sem.c: spelling fix 2021-05-07 00:26:34 -07:00
kernel Two fixes for timers: 2021-05-16 09:42:13 -07:00
lib kasan: fix unit tests with CONFIG_UBSAN_LOCAL_BOUNDS enabled 2021-05-14 19:41:32 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/ioremap: fix iomap_max_page_shift 2021-05-14 19:41:32 -07:00
net mm: fix struct page layout on 32-bit systems 2021-05-14 19:41:32 -07:00
samples Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
scripts Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
security trusted-keys: match tpm_get_ops on all return paths 2021-05-12 22:36:37 +03:00
sound sound fixes for 5.13-rc1 2021-05-07 11:40:18 -07:00
tools - Enable -Wundef for the compressed kernel build stage 2021-05-16 09:31:06 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt kvm: Cap halt polling at kvm->max_halt_poll_ns 2021-05-07 06:06:22 -04:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap Merge drm/drm-fixes into drm-misc-fixes 2021-05-11 13:35:52 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge tag 'amd-drm-next-5.14-2021-05-19' of https://gitlab.freedesktop.org/agd5f/linux into drm-next 2021-05-21 15:29:40 +10:00
Makefile Linux 5.13-rc2 2021-05-16 15:27:44 -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.