drm/i915: Add new GET_PIPE_FROM_CRTC_ID ioctl.

This allows userlevel code to discover the pipe number corresponding
to a given CRTC ID. This is necessary for doing pipe-specific
operations such as waiting for vblank on a given CRTC.  Failure to use
the right pipe mapping can result in GPU hangs, or at least failure
to actually sync to vblank.

Signed-off-by: Carl Worth <cworth@cworth.org>
[anholt: Style touchups from review]
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index 95962fa8398a..8e1e92583fbc 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -184,6 +184,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_I915_GEM_GET_TILING 0x22
 #define DRM_I915_GEM_GET_APERTURE 0x23
 #define DRM_I915_GEM_MMAP_GTT   0x24
+#define DRM_I915_GET_PIPE_FROM_CRTC_ID  0x25
 
 #define DRM_IOCTL_I915_INIT             DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
 #define DRM_IOCTL_I915_FLUSH            DRM_IO ( DRM_COMMAND_BASE + DRM_I915_FLUSH)
@@ -219,6 +220,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_GEM_SET_TILING   DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_SET_TILING, struct drm_i915_gem_set_tiling)
 #define DRM_IOCTL_I915_GEM_GET_TILING   DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_GET_TILING, struct drm_i915_gem_get_tiling)
 #define DRM_IOCTL_I915_GEM_GET_APERTURE DRM_IOR  (DRM_COMMAND_BASE + DRM_I915_GEM_GET_APERTURE, struct drm_i915_gem_get_aperture)
+#define DRM_IOCTL_I915_GET_PIPE_FROM_CRTC_ID DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GET_PIPE_FROM_CRTC_ID, struct drm_intel_get_pipe_from_crtc_id)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -657,4 +659,12 @@ struct drm_i915_gem_get_aperture {
         __u64 aper_available_size;
 };
 
+struct drm_i915_get_pipe_from_crtc_id {
+        /** ID of CRTC being requested **/
+        __u32 crtc_id;
+
+        /** pipe of requested CRTC **/
+        __u32 pipe;
+};
+
 #endif                          /* _I915_DRM_H_ */