Re: [PATCH 08/17] drm/plane-helper: transitional atomic plane helpers

On Wed, Nov 5, 2014 at 5:45 PM, Sean Paul seanpaul@chromium.org wrote:

...

• /* There's no other way to figure out whether the crtc is running. */
• ret = drm_crtc_vblank_get(crtc[i]);
• if (ret == 0) {
• drm_crtc_wait_one_vblank(crtc[i]);
• drm_crtc_vblank_put(crtc[i]);
• }

This will be good motivation for driver writers to convert to universal planes!

The problem here is actually dpms. Our current dpms interface sucks badly, since from generic code it's completely impossible to figure out whether the pipe is still on or somehow disabled due to dpms. I'm pondering ideas and designs right now, but my current dpms plan for atomic includes a fix for this. So with that I'd replace this hack with crtc->state->active check and add a WARN_ON to make sure the drm_vblank_get doesn't fail when the pipe is supposed to be on. -Daniel