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Wayne Lin 3769e4c0af drm/dp_mst: Avoid to mess up payload table by ports in stale topology
[Why]
After unplug/hotplug hub from the system, userspace might start to
clear stale payloads gradually. If we call drm_dp_mst_deallocate_vcpi()
to release stale VCPI of those ports which are not relating to current
topology, we have chane to wrongly clear active payload table entry for
current topology.

E.g.
We have allocated VCPI 1 in current payload table and we call
drm_dp_mst_deallocate_vcpi() to clean VCPI 1 in stale topology. In
drm_dp_mst_deallocate_vcpi(), it will call drm_dp_mst_put_payload_id()
tp put VCPI 1 and which means ID 1 is available again. Thereafter, if we
want to allocate a new payload stream, it will find ID 1 is available by
drm_dp_mst_assign_payload_id(). However, ID 1 is being used

[How]
Check target sink is relating to current topology or not before doing
any payload table update.
Searching upward to find the target sink's relevant root branch device.
If the found root branch device is not the same root of current
topology, don't update payload table.

Changes since v1:
* Change debug macro to use drm_dbg_kms() instead
* Amend the commit message to add Cc tag.

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210616035501.3776-3-Wayne.Lin@amd.com
Reviewed-by: Lyude Paul <lyude@redhat.com>
2021-06-16 12:57:46 -04:00
Documentation Merge tag 'amd-drm-next-5.14-2021-06-09' of https://gitlab.freedesktop.org/agd5f/linux into drm-next 2021-06-10 13:47:13 +10:00
LICENSES
arch Cross-subsystem Changes: 2021-06-10 13:45:11 +10:00
block block-5.13-2021-05-22 2021-05-22 07:40:34 -10:00
certs
crypto
drivers drm/dp_mst: Avoid to mess up payload table by ports in stale topology 2021-06-16 12:57:46 -04:00
fs userfaultfd: hugetlbfs: fix new flag usage in error path 2021-05-22 15:09:07 -10:00
include Merge branch 'etnaviv/next' of https://git.pengutronix.de/git/lst/linux into drm-next 2021-06-11 13:00:58 +10:00
init
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-22 15:09:07 -10:00
kernel Two locking fixes: 2021-05-23 06:30:08 -10:00
lib lib: kunit: suppress a compilation warning of frame size 2021-05-22 15:09:07 -10:00
mm userfaultfd: hugetlbfs: fix new flag usage in error path 2021-05-22 15:09:07 -10:00
net Char/misc driver fixes for 5.13-rc3 2021-05-20 06:31:52 -10:00
samples
scripts kbuild: dummy-tools: adjust to stricter stackprotector check 2021-05-17 12:10:03 +09:00
security
sound sound fixes for 5.13-rc3 2021-05-20 06:42:21 -10:00
tools powerpc fixes for 5.13 #4 2021-05-23 06:07:33 -10:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Add maintainer for hyperv video device 2021-06-07 08:04:10 -07:00
Makefile Linux 5.13-rc3 2021-05-23 11:42:48 -10:00
README

README

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.