[ Upstream commit 90c0486a82 ]
The Tiled Display Topology ID of a DisplayID Tiled Display Topology Data
Block consists of three fields:
- Tiled Display Manufacturer/Vendor ID Field (3 bytes)
- Tiled Display Product ID Code Field (2 bytes)
- Tiled Display Serial Number Field (4 bytes)
i.e. a total of 9 bytes, not 8.
The DisplayID Tiled Display Topology ID is used as the tile group
identifier.
Update both struct displayid_tiled_block topology_id member and struct
drm_tile_group group_data member to full 9 bytes.
The group data was missing the last byte of the serial number. I don't
know whether there are known bug reports that might be linked to this,
but it's plausible the last byte could be the differentiating part for
the tile groups, and fewer tile groups might have been created than
intended.
Fixes: b49b55bd4f ("drm/displayid: add displayid defines and edid extension (v2)")
Fixes: 138f9ebb97 ("drm: add tile_group support. (v3)")
Cc: Dave Airlie <airlied@redhat.com>
Cc: stable@vger.kernel.org # v3.19+
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: https://patch.msgid.link/20260610141549.555605-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
96b7b80fde