drm/amd/display: Fix ACPI edid parsing on some Lenovo systems

[Why]
The ACPI EDID in the BIOS of a Lenovo laptop includes 3 blocks, but
dm_helpers_probe_acpi_edid() has a start that is 'char'.  The 3rd
block index starts after 255, so it can't be indexed properly.
This leads to problems with the display when the EDID is parsed.

[How]
Change the variable type to 'short' so that larger values can be indexed.

Cc: Renjith Pananchikkal <renjith.pananchikkal@amd.com>
Reported-by: Mark Pearson <mpearson@lenovo.com>
Suggested-by: David Ober <dober@lenovo.com>
Fixes: c6a837088b ("drm/amd/display: Fetch the EDID from _DDC if available for eDP")
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Mario Limonciello 2025-04-04 09:34:52 -05:00 committed by Alex Deucher
parent ce2e117bfb
commit a918bb4a90

View File

@ -931,7 +931,7 @@ dm_helpers_probe_acpi_edid(void *data, u8 *buf, unsigned int block, size_t len)
{
struct drm_connector *connector = data;
struct acpi_device *acpidev = ACPI_COMPANION(connector->dev->dev);
unsigned char start = block * EDID_LENGTH;
unsigned short start = block * EDID_LENGTH;
struct edid *edid;
int r;