From:   Yaroslav Bolyukin <iam@lach.pw>
To:     amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Cc:     Harry Wentland <harry.wentland@amd.com>,
        Leo Li <sunpeng.li@amd.com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Jani Nikula <jani.nikula@intel.com>,
        Yaroslav Bolyukin <iam@lach.pw>
Subject: [PATCH v3] drm/edid DSC pass-through timing support
Date:   Sun, 26 Feb 2023 15:10:49 +0100
Message-Id: <20230226141051.21767-1-iam@lach.pw>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

VESA DisplayID spec allows the device to force its DSC bits per pixel
value.

For example, the HTC Vive Pro 2 VR headset uses this value in
high-resolution modes (3680x1836@90-120, 4896x2448@90-120), and when the
kernel doesn't respect this parameter, the garbage is displayed on HMD
instead.

I am unaware of any other hardware using this value; however, multiple
users have tested this patch on the Vive Pro 2, and it is known to work and
not break anything else.

Regarding driver support - I have looked at amdgpu and Nvidia's
open-gpu-kernel-modules, and both seem to have some indication for this
value; however, in Linux, it is unused in both. 

Amdgpu integration was trivial, so I implemented it in the second patch;
other kernel drivers still need the support of this value, and I don't have
the necessary hardware to implement and test the handling of this value on
them.

BR,
Yaroslav

Yaroslav Bolyukin (2):
  drm/edid: parse DRM VESA dsc bpp target
  drm/amd: use fixed dsc bits-per-pixel from edid

 .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c |  2 +
 .../gpu/drm/amd/display/dc/core/dc_stream.c   |  2 +
 drivers/gpu/drm/amd/display/dc/dc_types.h     |  3 ++
 drivers/gpu/drm/drm_edid.c                    | 42 ++++++++++++-------
 include/drm/drm_connector.h                   |  6 +++
 include/drm/drm_displayid.h                   |  4 ++
 6 files changed, 45 insertions(+), 14 deletions(-)


base-commit: a48bba98380cb0b43dcd01d276c7efc282e3c33f
--
2.39.1