From: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
To enable aspect-ratio support in DRM, blindly exposing the aspect
ratio information along with mode, can break things in existing
user-spaces which have no intention or support to use this aspect
ratio information.
To avoid this, a new drm client cap is required to enable a
user-space to advertise if it supports modes with aspect-ratio. Based
on this cap value, the kernel will take a call on exposing the aspect
ratio info in modes or not.
This patch adds the client cap for aspect-ratio.
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Shashank Sharma <shashank.sharma@xxxxxxxxx>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
V3: rebase
V4: As suggested by Marteen Lankhorst modified the commit message
explaining the need to use the DRM cap for aspect-ratio. Also,
tweaked the comment lines in the code for better understanding and
clarity, as recommended by Shashank Sharma.
V5: rebase
V6: rebase
V7: rebase
V8: rebase
V9: rebase
V10: added comment explaining that no userspace breaks on aspect-ratio
mode bits.
Reviewed-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
---
drivers/gpu/drm/drm_ioctl.c | 9 +++++++++
include/drm/drm_file.h | 8 ++++++++
include/uapi/drm/drm.h | 7 +++++++
3 files changed, 24 insertions(+)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index af78291..39c8eab 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -325,6 +325,15 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
file_priv->atomic = req->value;
file_priv->universal_planes = req->value;
break;
+ case DRM_CLIENT_CAP_ASPECT_RATIO:
+ if (req->value > 1)
+ return -EINVAL;
+ /*
+ * No Atomic userspace blows up on aspect ratio mode bits. Checked in
+ * wayland/weston, xserver, and hardware-composer modeset paths.
+ */
+ file_priv->aspect_ratio_allowed = req->value;
+ break;
default:
return -EINVAL;
}
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 5176c37..02b7dde 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -182,6 +182,14 @@ struct drm_file {
unsigned atomic:1;
/**
+ * @aspect_ratio_allowed:
+ *
+ * True, if client can handle picture aspect ratios, and has requested
+ * to pass this information along with the mode.
+ */
+ unsigned aspect_ratio_allowed:1;
+
+ /**
* @is_master:
*
* This client is the creator of @master. Protected by struct
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 6fdff59..9c660e1 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -680,6 +680,13 @@ struct drm_get_cap {
*/
#define DRM_CLIENT_CAP_ATOMIC 3
+/**
+ * DRM_CLIENT_CAP_ASPECT_RATIO
+ *
+ * If set to 1, the DRM core will provide aspect ratio information in modes.
+ */
+#define DRM_CLIENT_CAP_ASPECT_RATIO 4
+
/** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
struct drm_set_client_cap {
__u64 capability;
--
2.7.4
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