Re: [PATCH 1/2] radeon: Don't generate new fence for page flip.

[Alex Deucher <alexdeucher@gmail.com>]

2011/7/12 Michel Dänzer <michel@daenzer.net>:
> From: Michel Dänzer <michel.daenzer@amd.com>
>
> Use the fence of the new frontbuffer, if any.
>
> Generating a new fence could cause us to wait for completely unrelated
> rendering to finish before performing the flip.
>
> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

> ---
>  drivers/gpu/drm/radeon/radeon_display.c |   33 ++++--------------------------
>  1 files changed, 5 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
> index 0671934..71a4840 100644
> --- a/drivers/gpu/drm/radeon/radeon_display.c
> +++ b/drivers/gpu/drm/radeon/radeon_display.c
> @@ -280,7 +280,7 @@ void radeon_crtc_handle_flip(struct radeon_device *rdev, int crtc_id)
>        spin_lock_irqsave(&rdev->ddev->event_lock, flags);
>        work = radeon_crtc->unpin_work;
>        if (work == NULL ||
> -           !radeon_fence_signaled(work->fence)) {
> +           (work->fence && !radeon_fence_signaled(work->fence))) {
>                spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
>                return;
>        }
> @@ -346,7 +346,6 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
>        struct radeon_framebuffer *new_radeon_fb;
>        struct drm_gem_object *obj;
>        struct radeon_bo *rbo;
> -       struct radeon_fence *fence;
>        struct radeon_unpin_work *work;
>        unsigned long flags;
>        u32 tiling_flags, pitch_pixels;
> @@ -357,22 +356,19 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
>        if (work == NULL)
>                return -ENOMEM;
>
> -       r = radeon_fence_create(rdev, &fence);
> -       if (unlikely(r != 0)) {
> -               kfree(work);
> -               DRM_ERROR("flip queue: failed to create fence.\n");
> -               return -ENOMEM;
> -       }
>        work->event = event;
>        work->rdev = rdev;
>        work->crtc_id = radeon_crtc->crtc_id;
> -       work->fence = radeon_fence_ref(fence);
>        old_radeon_fb = to_radeon_framebuffer(crtc->fb);
>        new_radeon_fb = to_radeon_framebuffer(fb);
>        /* schedule unpin of the old buffer */
>        obj = old_radeon_fb->obj;
>        rbo = gem_to_radeon_bo(obj);
>        work->old_rbo = rbo;
> +       obj = new_radeon_fb->obj;
> +       rbo = gem_to_radeon_bo(obj);
> +       if (rbo->tbo.sync_obj)
> +               work->fence = radeon_fence_ref(rbo->tbo.sync_obj);
>        INIT_WORK(&work->work, radeon_unpin_work_func);
>
>        /* We borrow the event spin lock for protecting unpin_work */
> @@ -380,7 +376,6 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
>        if (radeon_crtc->unpin_work) {
>                spin_unlock_irqrestore(&dev->event_lock, flags);
>                kfree(work);
> -               radeon_fence_unref(&fence);
>
>                DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
>                return -EBUSY;
> @@ -390,9 +385,6 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
>        spin_unlock_irqrestore(&dev->event_lock, flags);
>
>        /* pin the new buffer */
> -       obj = new_radeon_fb->obj;
> -       rbo = gem_to_radeon_bo(obj);
> -
>        DRM_DEBUG_DRIVER("flip-ioctl() cur_fbo = %p, cur_bbo = %p\n",
>                         work->old_rbo, rbo);
>
> @@ -460,25 +452,11 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
>                goto pflip_cleanup1;
>        }
>
> -       /* 32 ought to cover us */
> -       r = radeon_ring_lock(rdev, 32);
> -       if (r) {
> -               DRM_ERROR("failed to lock the ring before flip\n");
> -               goto pflip_cleanup2;
> -       }
> -
> -       /* emit the fence */
> -       radeon_fence_emit(rdev, fence);
>        /* set the proper interrupt */
>        radeon_pre_page_flip(rdev, radeon_crtc->crtc_id);
> -       /* fire the ring */
> -       radeon_ring_unlock_commit(rdev);
>
>        return 0;
>
> -pflip_cleanup2:
> -       drm_vblank_put(dev, radeon_crtc->crtc_id);
> -
>  pflip_cleanup1:
>        r = radeon_bo_reserve(rbo, false);
>        if (unlikely(r != 0)) {
> @@ -498,7 +476,6 @@ pflip_cleanup:
>        spin_lock_irqsave(&dev->event_lock, flags);
>        radeon_crtc->unpin_work = NULL;
>        spin_unlock_irqrestore(&dev->event_lock, flags);
> -       radeon_fence_unref(&fence);
>        kfree(work);
>
>        return r;
> --
> 1.7.5.4
>
>
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