Add new drm_intel_get_pipe_from_crtc_id function.

This wraps the new DRM_IOCTL_I915_GET_PIPE_FROM_CRTC_ID ioctl,
allowing applications 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.

2 files changed, 25 insertions, 0 deletions

diff --git a/libdrm/intel/intel_bufmgr.h b/libdrm/intel/intel_bufmgr.h
index 75d06cad..758558df 100644
--- a/libdrm/intel/intel_bufmgr.h
+++ b/libdrm/intel/intel_bufmgr.h
@@ -120,6 +120,8 @@ int drm_intel_gem_bo_map_gtt(drm_intel_bo *bo);
 int drm_intel_gem_bo_unmap_gtt(drm_intel_bo *bo);
 void drm_intel_gem_bo_start_gtt_access(drm_intel_bo *bo, int write_enable);
 
+int drm_intel_get_pipe_from_crtc_id(drm_intel_bufmgr *bufmgr, int crtc_id);
+
 /* drm_intel_bufmgr_fake.c */
 drm_intel_bufmgr *drm_intel_bufmgr_fake_init(int fd,
 					     unsigned long low_offset,
diff --git a/libdrm/intel/intel_bufmgr_gem.c b/libdrm/intel/intel_bufmgr_gem.c
index 5ae4d668..3f792da1 100644
--- a/libdrm/intel/intel_bufmgr_gem.c
+++ b/libdrm/intel/intel_bufmgr_gem.c
@@ -815,6 +815,29 @@ drm_intel_gem_bo_subdata (drm_intel_bo *bo, unsigned long offset,
     return 0;
 }
 
+int
+drm_intel_get_pipe_from_crtc_id (drm_intel_bufmgr *bufmgr, int crtc_id)
+{
+    drm_intel_bufmgr_gem *bufmgr_gem = (drm_intel_bufmgr_gem *) bufmgr;
+    struct drm_i915_get_pipe_from_crtc_id get_pipe_from_crtc_id;
+    int ret;
+
+    get_pipe_from_crtc_id.crtc_id = crtc_id;
+    ret = ioctl (bufmgr_gem->fd, DRM_IOCTL_I915_GET_PIPE_FROM_CRTC_ID,
+		 &get_pipe_from_crtc_id);
+    if (ret != 0) {
+	/* We're intentionally silent here so that there is no
+	 * complaint when simply running with an older kernel that
+	 * doesn't have the GET_PIPE_FROM_CRTC_ID ioctly. In that
+	 * case, we just punt and try to sync on pipe 0, which is
+	 * hopefully the right pipe in some cases at least.
+	 */
+	return 0;
+    }
+
+    return get_pipe_from_crtc_id.pipe;
+}
+
 static int
 drm_intel_gem_bo_get_subdata (drm_intel_bo *bo, unsigned long offset,
 			      unsigned long size, void *data)