On Thu, Sep 27, 2012 at 09:25:58PM +0100, Chris Wilson wrote:
> This was meant to be the purpose of the
> intel_crtc_wait_for_pending_flips() function which is called whilst
> preparing the CRTC for a modeset or before disabling. However, as Ville
> Syrjala pointed out, we set the pending flip notification on the old
> framebuffer that is no longer attached to the CRTC by the time we come
> to flush the pending operations. Instead, we can simply wait on the
> pending unpin work to be finished on this CRTC, knowning that the
> hardware has therefore finished modifying the registers, before proceeding
> with our direct access.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Can I haz testcase plz?
Shouldn't be too hard to race a few pageflips with dpms off and crtc
disabling, maybe we need to add some busy load onto the gpu first to delay
things for long enough.
Thanks, Daniel
> ---
> drivers/gpu/drm/i915/intel_display.c | 24 ++++++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a262326..39df185 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2896,15 +2896,36 @@ static void ironlake_fdi_disable(struct drm_crtc *crtc)
> udelay(100);
> }
>
> +static bool intel_crtc_has_pending_flip(struct drm_crtc *crtc)
> +{
> + struct drm_device *dev = crtc->dev;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + unsigned long flags;
> + bool pending;
> +
> + if (atomic_read(&dev_priv->mm.wedged))
> + return false;
> +
> + spin_lock_irqsave(&dev->event_lock, flags);
> + pending = to_intel_crtc(crtc)->unpin_work != NULL;
> + spin_unlock_irqrestore(&dev->event_lock, flags);
> +
> + return pending;
> +}
> +
> static void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
> {
> struct drm_device *dev = crtc->dev;
> + struct drm_i915_private *dev_priv = dev->dev_private;
>
> flush_work_sync(&to_intel_crtc(crtc)->vblank_work.work);
>
> if (crtc->fb == NULL)
> return;
>
> + wait_event(dev_priv->pending_flip_queue,
> + !intel_crtc_has_pending_flip(crtc));
> +
> mutex_lock(&dev->struct_mutex);
> intel_finish_fb(crtc->fb);
> mutex_unlock(&dev->struct_mutex);
> @@ -6388,9 +6409,8 @@ static void do_intel_finish_page_flip(struct drm_device *dev,
>
> atomic_clear_mask(1 << intel_crtc->plane,
> &obj->pending_flip.counter);
> - if (atomic_read(&obj->pending_flip) == 0)
> - wake_up(&dev_priv->pending_flip_queue);
>
> + wake_up(&dev_priv->pending_flip_queue);
> queue_work(dev_priv->wq, &work->work);
>
> trace_i915_flip_complete(intel_crtc->plane, work->pending_flip_obj);
> --
> 1.7.10.4
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
