Karthikeyan Ramasubramanian 43b26bdd2e drm/i915/bios: Fix parsing backlight BDB data
Starting BDB version 239, hdr_dpcd_refresh_timeout is introduced to
backlight BDB data. Commit 700034566d ("drm/i915/bios: Define more BDB
contents") updated the backlight BDB data accordingly. This broke the
parsing of backlight BDB data in VBT for versions 236 - 238 (both
inclusive) and hence the backlight controls are not responding on units
with the concerned BDB version.

backlight_control information has been present in backlight BDB data
from at least BDB version 191 onwards, if not before. Hence this patch
extracts the backlight_control information for BDB version 191 or newer.
Tested on Chromebooks using Jasperlake SoC (reports bdb->version = 236).
Tested on Chromebooks using Raptorlake SoC (reports bdb->version = 251).

v2: removed checking the block size of the backlight BDB data
    [vsyrjala: this is completely safe thanks to commit e163cfb4c9
     ("drm/i915/bios: Make copies of VBT data blocks")]

Fixes: 700034566d ("drm/i915/bios: Define more BDB contents")
Cc: stable@vger.kernel.org
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@chromium.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240221180622.v2.1.I0690aa3e96a83a43b3fc33f50395d334b2981826@changeid
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
(cherry picked from commit c286f6a973)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
2024-05-07 09:42:27 -04:00
2024-05-05 14:00:48 -07:00
2022-09-28 09:02:20 +02:00
2024-05-05 14:06:01 -07:00
2024-03-18 03:36:32 -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 reStructuredText 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.
S
Description
No description provided
Readme
5.6 GiB
Languages
C 96.9%
Assembly 0.9%
Rust 0.6%
Shell 0.6%
Python 0.5%
Other 0.3%