On Wed, Jul 30, 2014 at 05:32:28PM +0900, Michel Dänzer wrote:
On 30.07.2014 17:22, Daniel Vetter wrote:
On Wed, Jul 30, 2014 at 11:59:33AM +0900, Michel Dänzer wrote:
On 30.07.2014 06:32, Daniel Vetter wrote:
- due to lack of driver support or because the crtc is off.
- */
+void drm_crtc_vblank_wait(struct drm_crtc *crtc) +{
- drm_vblank_wait(crtc->dev, drm_crtc_index(crtc));
+} +EXPORT_SYMBOL(drm_crtc_vblank_wait);
+/**
Maybe the function names should be *_vblank_wait_next() or something to clarify the purpose and reduce potential confusion versus drm_wait_vblank().
Yeah that name is just transferred from the i915 driver. What about drm_wait_one_vblank()/drm_crtc_wait_one_vblank()?
I don't care that much :), go ahead.
Just my two cents: our downstream kernel has a helper somewhat like this which waits for a specified number of frames (apparently this is useful for some panels that require up to 5 or 6 frames before they display the correct image on screen). So perhaps something like this could work:
void drm_wait_vblank_count(struct drm_device *dev, unsigned int crtc, unsigned int count) { u32 last; int ret;
ret = drm_vblank_get(dev, crtc); if (WARN_ON(ret)) return;
while (count--) { last = drm_vblank_count(dev, crtc);
... }
drm_vblank_put(dev, crtc); }
Then implement drm_wait_vblank() (or drm_wait_one_vblank()) on top of that as a special case. Of course one could equally well implement drm_wait_vblank_count() on top of your drm_wait_{one_,}vblank().
I couldn't think of a safe way to make the above work without the loop...
Thierry