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>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index bdcda36..3387cf3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1804,6 +1804,37 @@
}
}
+int intel_get_pipe_from_crtc_id(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ struct drm_i915_get_pipe_from_crtc_id *pipe_from_crtc_id = data;
+ struct drm_crtc *crtc = NULL;
+ int pipe = -1;
+
+ if (!dev_priv) {
+ DRM_ERROR("called with no initialization\n");
+ return -EINVAL;
+ }
+
+ list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+ struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+ if (crtc->base.id == pipe_from_crtc_id->crtc_id) {
+ pipe = intel_crtc->pipe;
+ break;
+ }
+ }
+
+ if (pipe == -1) {
+ DRM_ERROR("no such CRTC id\n");
+ return -EINVAL;
+ }
+
+ pipe_from_crtc_id->pipe = pipe;
+
+ return 0;
+}
+
struct drm_crtc *intel_get_crtc_from_pipe(struct drm_device *dev, int pipe)
{
struct drm_crtc *crtc = NULL;