drm/dp_mst: Add new quirk for Synaptics MST hubs
Synaptics DP1.4 hubs (BRANCH_ID 0x90CC24) do not
support virtual DPCD registers, but do support DSC.
The DSC caps can be read from the physical aux,
like in SST DSC. These hubs have many different
DEVICE_IDs. Add a new quirk to detect this case.
v2: Fix error when checking return of drm_dp_read_desc
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: David Francis <David.Francis@amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 8f8f363..0aeaf4a 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1522,6 +1522,13 @@ enum drm_dp_quirk {
* The driver should ignore SINK_COUNT during detection.
*/
DP_DPCD_QUIRK_NO_SINK_COUNT,
+ /**
+ * @DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD:
+ *
+ * The device supports MST DSC despite not supporting Virtual DPCD.
+ * The DSC caps can be read from the physical aux instead.
+ */
+ DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD,
};
/**