[Intel-gfx] [PATCH v2 1/9] drm/edid: Clarify why we only accept the "range limits only" descriptor

Ville Syrjala ville.syrjala at linux.intel.com
Tue Sep 27 16:59:58 UTC 2022


From: Ville Syrjälä <ville.syrjala at linux.intel.com>

The current comment fails to clarify why we only accept
the "range limits only" variant of the range descriptor.
Reword it to make some actual sense.

Cc: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
Cc: Harry Wentland <harry.wentland at amd.com>
Cc: Leo Li <sunpeng.li at amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
Cc: amd-gfx at lists.freedesktop.org
Reviewed-by: Manasi Navare <manasi.d.navare at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/drm_edid.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 4005dab6147d..ac662495635c 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -6033,10 +6033,13 @@ void get_monitor_range(const struct detailed_timing *timing, void *c)
 		return;
 
 	/*
-	 * Check for flag range limits only. If flag == 1 then
-	 * no additional timing information provided.
-	 * Default GTF, GTF Secondary curve and CVT are not
-	 * supported
+	 * These limits are used to determine the VRR refresh
+	 * rate range. Only the "range limits only" variant
+	 * of the range descriptor seems to guarantee that
+	 * any and all timings are accepted by the sink, as
+	 * opposed to just timings conforming to the indicated
+	 * formula (GTF/GTF2/CVT). Thus other variants of the
+	 * range descriptor are not accepted here.
 	 */
 	if (range->flags != DRM_EDID_RANGE_LIMITS_ONLY_FLAG)
 		return;
-- 
2.35.1



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