[PATCH v7 5/9] drm: Handle aspect-ratio info in getblob

[Nautiyal, Ankit K]

From: Ankit Nautiyal <ankit.k.nautiyal at intel.com>

If the user-space does not support aspect-ratio, then getblob called
with the blob id of a user-mode, should clear the aspect-ratio
information in the blob data.

Currently for a given blob id, there is no way to determine if the
blob stores user-mode or not. This can only be ascertained when the
blob is used for an atomic modeset call.

This patch:
-adds a new field 'is_video_mode' in drm_property_blob to
 differentiate between the video mode blobs and the other blobs.
-sets the field 'is_video_mode' when the blob is used for modeset.
-removes the aspect-ratio info from the user-mode data if aspect-ratio
 is not supported by the user, while returning the blob to the user,
 in getblob ioctl.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>

V6: As suggested by Ville:
    -added helper functions for determining if aspect-ratio is
     expected in user-mode and for allowing/disallowing the
     aspect-ratio, if its not expected.
    -avoided clobbering of blob-data, instead cleared the aspect-ratio
     in the user-mode only, so that another client with aspect-ratio
     cap, can still get the aspect-ratio information from getblob.
V7: Fixed warning [Wint-to-pointer-cast] for 32 bit platforms.
---
 drivers/gpu/drm/drm_atomic.c   |  1 +
 drivers/gpu/drm/drm_modes.c    | 44 ++++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_property.c |  5 +++++
 include/drm/drm_modes.h        |  4 ++++
 include/drm/drm_property.h     |  2 ++
 5 files changed, 56 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 34b7d42..2b1c88a 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -464,6 +464,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 	else if (property == config->prop_mode_id) {
 		struct drm_property_blob *mode =
 			drm_property_lookup_blob(dev, val);
+		mode->is_video_mode = true;
 		ret = drm_atomic_set_mode_prop_for_crtc(state, mode);
 		drm_property_blob_put(mode);
 		return ret;
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index a48672c..4430294 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1761,3 +1761,47 @@ bool drm_mode_is_420(const struct drm_display_info *display,
 		drm_mode_is_420_also(display, mode);
 }
 EXPORT_SYMBOL(drm_mode_is_420);
+
+/**
+ * drm_mode_aspect_ratio_allowed - checks if the aspect-ratio information
+ * is expected from the user-mode.
+ *
+ * If the user has set aspect-ratio cap, then the flag of the user-mode is
+ * allowed to contain aspect-ratio value.
+ * If the user does not set aspect-ratio cap, then the only value allowed in the
+ * flags bits is aspect-ratio NONE.
+ *
+ * @file_priv: file private structure to get the user capabilities
+ * @flags: 32 bit flag that contains the aspect-ratio information.
+ *
+ * Returns:
+ * true if the aspect-ratio info is allowed in the user-mode flags.
+ * false, otherwise.
+ */
+bool
+drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv, uint32_t flags)
+{
+	return file_priv->aspect_ratio_allowed ||
+	       (flags & DRM_MODE_FLAG_PIC_AR_MASK) == DRM_MODE_FLAG_PIC_AR_NONE;
+}
+EXPORT_SYMBOL(drm_mode_aspect_ratio_allowed);
+
+/**
+ * drm_mode_handle_aspect_ratio - handles the aspect-ratio bits in the user-mode
+ * flags.
+ *
+ * Checks if the aspect-ratio information is allowed. Resets the aspect-ratio
+ * bits in the user-mode flag, if aspect-ratio info is not allowed.
+ *
+ * @file_priv: file private structure to get the user capabilities.
+ * @flags: 32 bit flag that is to be modified, in case the aspect
+ * ratio info is not allowed.
+ *
+ */
+void
+drm_mode_handle_aspect_ratio(const struct drm_file *file_priv, uint32_t *flags)
+{
+	if (!drm_mode_aspect_ratio_allowed(file_priv, *flags))
+		*flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
+}
+EXPORT_SYMBOL(drm_mode_handle_aspect_ratio);
diff --git a/drivers/gpu/drm/drm_property.c b/drivers/gpu/drm/drm_property.c
index c37ac41..0a9c879 100644
--- a/drivers/gpu/drm/drm_property.c
+++ b/drivers/gpu/drm/drm_property.c
@@ -757,6 +757,11 @@ int drm_mode_getblob_ioctl(struct drm_device *dev,
 			ret = -EFAULT;
 			goto unref;
 		}
+		if (blob->is_video_mode) {
+			struct drm_mode_modeinfo __user *mode =
+				u64_to_user_ptr(out_resp->data);
+			drm_mode_handle_aspect_ratio(file_priv, &mode->flags);
+		}
 	}
 	out_resp->length = blob->length;
 unref:
diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
index 2f78b7e..51d1188 100644
--- a/include/drm/drm_modes.h
+++ b/include/drm/drm_modes.h
@@ -461,6 +461,10 @@ bool drm_mode_is_420_also(const struct drm_display_info *display,
 			  const struct drm_display_mode *mode);
 bool drm_mode_is_420(const struct drm_display_info *display,
 		     const struct drm_display_mode *mode);
+bool drm_mode_aspect_ratio_allowed(const struct drm_file *file_priv,
+				   uint32_t flags);
+void drm_mode_handle_aspect_ratio(const struct drm_file *file_priv,
+				  uint32_t *flags);
 
 struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
 				      int hdisplay, int vdisplay, int vrefresh,
diff --git a/include/drm/drm_property.h b/include/drm/drm_property.h
index 8a522b4..95e6e32 100644
--- a/include/drm/drm_property.h
+++ b/include/drm/drm_property.h
@@ -194,6 +194,7 @@ struct drm_property {
  * @head_global: entry on the global blob list in
  * 	&drm_mode_config.property_blob_list.
  * @head_file: entry on the per-file blob list in &drm_file.blobs list.
+ * @is_video_mode: flag to mark the blobs that contain drm_mode_modeinfo.
  * @length: size of the blob in bytes, invariant over the lifetime of the object
  * @data: actual data, embedded at the end of this structure
  *
@@ -208,6 +209,7 @@ struct drm_property_blob {
 	struct drm_device *dev;
 	struct list_head head_global;
 	struct list_head head_file;
+	bool is_video_mode;
 	size_t length;
 	unsigned char data[];
 };
-- 
2.7.4