35511d4fdd
commit 0ea917819d12fed41ea4662cc26ffa0060a5c354 upstream.
The VBT send packet port selection was never updated for ICL+ where the
2nd link is on port B instead of port C as in VLV+ DSI.
First, single link DSI needs to use the configured port instead of
relying on the VBT sequence block port. Remove the hard-coded port C
check here and make it generic. For reference, see commit f915084edc5a
("drm/i915: Changes related to the sequence port no for") for the
original VLV specific fix.
Second, the sequence block port number is either 0 or 1, where 1
indicates the 2nd link. Remove the hard-coded port C here for 2nd
link. (This could be a "find second set bit" on DSI ports, but just
check the two possible options.)
Third, sanity check the result with a warning to avoid a NULL pointer
dereference.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5984
Cc: stable@vger.kernel.org # v4.19+
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220520094600.2066945-1-jani.nikula@intel.com
(cherry picked from commit 08c59dde71b73a0ac94e3ed2d431345b01f20485)
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.