User-space should avoid parsing EDIDs for metadata already exposed via
other KMS interfaces and properties. For instance, user-space should not
try to extract a list of modes from the EDID: the kernel might mutate
the mode list (because of link capabilities or quirks for instance).
Other metadata not exposed by KMS can be parsed by user-space. This
includes for instance monitor identification (make/model/serial) and
supported color-spaces.
v2: add short explanation why user-space shouldn't do this (Brian)
Signed-off-by: Simon Ser <contact@xxxxxxxxxxx>
Suggested-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Brian Starkey <brian.starkey@xxxxxxx>
---
drivers/gpu/drm/drm_connector.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 717c4e7271b0..1913d8b4e16a 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -960,6 +960,11 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {
* drm_connector_update_edid_property(), usually after having parsed
* the EDID using drm_add_edid_modes(). Userspace cannot change this
* property.
+ *
+ * User-space should not parse the EDID to obtain information exposed via
+ * other KMS properties (because the kernel might apply limits, quirks or
+ * fixups to the EDID). For instance, user-space should not try to parse
+ * mode lists from the EDID.
* DPMS:
* Legacy property for setting the power state of the connector. For atomic
* drivers this is only provided for backwards compatibility with existing
--
2.28.0
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