Commit 3bde449f authored May 29, 2019 by Ville Syrjälä

drm/edid: Ignore "DFP 1.x" bit for EDID 1.2 and earlier



From VESA EDID implementation guide v1.0:
"For EDID version 1 revision 2 or earlier data structures when offset 14h
 bit 7 is set to one, the value of bits 6-0 are undefined, and therefore
 cannot be interpreted to mean anything."

And since EDID 1.4 redefines that bit let's consult it only for
EDID 1.3.

Cc: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190529110204.2384-2-ville.syrjala@linux.intel.com


Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Mario Kleiner <mario.kleiner.de@gmail.com>

parent 382d2af6

drivers/gpu/drm/drm_edid.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -4569,8 +4569,8 @@ u32 drm_add_display_info(struct drm_connector connector, const struct edid edi
		* tells us to assume 8 bpc color depth if the EDID doesn't have
		* extensions which tell otherwise.
		*/
		if ((info->bpc == 0) && (edid->revision < 4) &&
		(edid->input & DRM_EDID_DIGITAL_DFP_1_X)) {
		if (info->bpc == 0 && edid->revision == 3 &&
		edid->input & DRM_EDID_DIGITAL_DFP_1_X) {
		info->bpc = 8;
		DRM_DEBUG("%s: Assigning DFP sink color depth as %d bpc.\n",
		connector->name, info->bpc);