bb693c114e
commit 92bd92c44d0d9be5dcbcda315b4be4b909ed9740 upstream.
Commit 2f015ec6eab6 ("drm/dp_mst: Add sideband down request tracing +
selftests") added some debug code for sideband message tracing. But
it seems to have unintentionally changed the behavior on sideband message
failure. It catches and returns failure only if DRM_UT_DP is enabled.
Otherwise it ignores the error code and returns success. So on an MST
unplug, the caller is unaware that the clear payload message failed and
ends up waiting for 4 seconds for the response. Fixes the issue by
returning the proper error code.
Changes in V2:
-- Revise commit text as review comment
-- add Fixes text
Changes in V3:
-- remove "unlikely" optimization
Fixes: 2f015ec6eab6 ("drm/dp_mst: Add sideband down request tracing + selftests")
Cc: <stable@vger.kernel.org> # v5.5+
Signed-off-by: Rajkumar Subbiah <rsubbia@codeaurora.org>
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1625585434-9562-1-git-send-email-khsieh@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.