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authorSimon Ser <contact@emersion.fr>2020-10-22 10:34:44 +0000
committerSimon Ser <contact@emersion.fr>2020-10-22 13:49:14 +0200
commit12767469edfad756491e4a95e86934b5c89b9685 (patch)
treeb663babb5a44f06e01649395db22cf13322cfc14 /drivers/gpu/drm
parent6a6e5988a2657cd0c91f6f1a3e7d194599248b6d (diff)
drm: document that user-space should avoid parsing EDIDs
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@emersion.fr> Suggested-by: Daniel Vetter <daniel.vetter@intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Brian Starkey <brian.starkey@arm.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Cc: Pekka Paalanen <pekka.paalanen@collabora.co.uk> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/V_APW3gKRhljvcmT28tGV3JkP7qW9Z7h45I-s2wiJvYhaaveCpYpg3tztZPsZVV2KV1NC7rUx08IUUgCJXzdRrWCsEGB0czq4ZozpdyVFLs=@emersion.fr
Diffstat (limited to 'drivers/gpu/drm')
-rw-r--r--drivers/gpu/drm/drm_connector.c5
1 files changed, 5 insertions, 0 deletions
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