Commit 7595bda2 authored May 08, 2018 by Ankit Nautiyal Committed by Maarten Lankhorst May 11, 2018

drm: Add DRM client cap for aspect-ratio



To enable aspect-ratio support in DRM, blindly exposing the aspect
ratio information along with mode, can break things in existing
non-atomic 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 non-atomic
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.

Since no atomic-userspaces blow up on receiving aspect-ratio
information, the client cap for aspect-ratio is always enabled
for atomic clients.

Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

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: rebase
V11: rebase
V12: As suggested by Daniel Vetter and Ville Syrjala,
     always enable aspect-ratio client cap for atomic userspaces,
     if no atomic userspace breaks on aspect-ratio bits.
V13: rebase
V14: rebase

Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1525777785-9740-7-git-send-email-ankit.k.nautiyal@intel.com

parent bfe2e2c9

drivers/gpu/drm/drm_ioctl.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -324,6 +324,15 @@ drm_setclientcap(struct drm_device dev, void data, struct drm_file *file_priv)
		return -EINVAL;
		file_priv->atomic = req->value;
		file_priv->universal_planes = req->value;
		/*
		* No atomic user-space blows up on aspect ratio mode bits.
		*/
		file_priv->aspect_ratio_allowed = req->value;
		break;
		case DRM_CLIENT_CAP_ASPECT_RATIO:
		if (req->value > 1)
		return -EINVAL;
		file_priv->aspect_ratio_allowed = req->value;
		break;
		default:
		return -EINVAL;

include/drm/drm_file.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -180,6 +180,14 @@ struct drm_file {
		/** @atomic: True if client understands atomic properties. */
		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:
		*

include/uapi/drm/drm.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -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;

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