[PATCH RFC 15/25] drm/edid: Parse QMS flag from HDMI SCDS

[Nicolas Frattaroli]

Thanks to a GPL'd source code release from a hardware vendor that shall
not be named, which has since been scrubbed off GitHub, it's now public
knowledge how the HDMI Forum EDID extension communicates support for QMS
("Quick Media Switching") on a sink. Bit number 6 indicates support for
QMS in the same byte that also contains the CinemaVRR flag.

Add this definition to the EDID header file, and parse it to a member of
drm_hdmi_info.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli at collabora.com>
---
 drivers/gpu/drm/drm_edid.c  | 1 +
 include/drm/drm_connector.h | 3 +++
 include/drm/drm_edid.h      | 1 +
 3 files changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index cc6f2ba8c9f4..5a7d3b7e65da 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -6318,6 +6318,7 @@ static void drm_parse_vrr_info(struct drm_display_info *info, const u8 *hf_scds)
 		return;
 
 	info->hdmi.cinema_vrr = !!(hf_scds[8] & DRM_EDID_CINEMA_VRR);
+	info->hdmi.qms_capable = !!(hf_scds[8] & DRM_EDID_QMS);
 
 	if (pld_len < 10)
 		return;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index b147b8474f1a..c97cf0625fda 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -386,6 +386,9 @@ struct drm_hdmi_info {
 
 	/** @cinema_vrr: The sink supports "CinemaVRR" */
 	bool cinema_vrr;
+
+	/** @qms_capable: The sink supports Quick Media Switching */
+	bool qms_capable;
 };
 
 /**
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index a2617aa34edf..f1e2052cb08b 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -265,6 +265,7 @@ struct detailed_timing {
 #define DRM_EDID_CNMVRR				(1 << 3)
 #define DRM_EDID_CINEMA_VRR			(1 << 4)
 #define DRM_EDID_MDELTA				(1 << 5)
+#define DRM_EDID_QMS				(1 << 6)
 #define DRM_EDID_VRR_MAX_UPPER_MASK		0xc0
 #define DRM_EDID_VRR_MAX_LOWER_MASK		0xff
 #define DRM_EDID_VRR_MIN_MASK			0x3f

-- 
2.55.0