[ Upstream commit cbd6c1b17d3b42b7935526a86ad5f66838767d03 ] [Why] In USB4 DP tunneling, it's possible to have this scenario that the path becomes unavailable and CM tears down the path a little bit late. So, in this case, the HPD is high but fails to read any DPCD register. That causes the link connection type to be set to sst. And not all sinks are removed behind the MST branch. [How] Restore the link connection type if it fails to read DPCD register. Cc: stable@vger.kernel.org Cc: Mario Limonciello <mario.limonciello@amd.com> Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com> Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com> Signed-off-by: Cruise Hung <Cruise.Hung@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> (cherry picked from commit cbd6c1b17d3b42b7935526a86ad5f66838767d03) Modified for stable backport as a lot of the code in this file was moved in 6.3 to drivers/gpu/drm/amd/display/dc/link/link_detection.c. Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.
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