Originally these functions have been for user modesetting drivers to ensure vblank processing doesn't fall over completely around modeset changes. This has been carried over ever since then.
Now that Ville cleaned our vblank handling with an explicit drm_vblank_off/on braket when disabling/enabling crtcs. So this seems to be unnecessary now. The most important side effect was that due to the delayed vblank disabling we have been pretty much guaranteed to receive a vblank interrupt soonish after a crtc was enabled.
Note that our vblank handling across modeset is still fairly decent fubar - we don't actually handle vblank counter all to well. drm_update_vblank_count will make sure that the frame counter always rolls forward, but userspace isn't really all to ready to cope with the big jumps this causes.
This isn't a big mostly because the hardware retains the frame counter. But with runtime pm and also across suspend/resume we fall over.
Fixing this is a lot more involved and also needs som i-g-ts. So material for another patch series.
Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/intel_display.c | 5 ----- 1 file changed, 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 858c393b051f..d0eff53a8ad1 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7207,15 +7207,10 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc, struct intel_encoder *encoder; struct intel_crtc *intel_crtc = to_intel_crtc(crtc); struct drm_display_mode *mode = &intel_crtc->config.requested_mode; - int pipe = intel_crtc->pipe; int ret;
- drm_vblank_pre_modeset(dev, pipe); - ret = dev_priv->display.crtc_mode_set(crtc, x, y, fb);
- drm_vblank_post_modeset(dev, pipe); - if (ret != 0) return ret;