[PATCH 5/5] drm/radeon: rework page flip handling v3

Alex Deucher alexdeucher at gmail.com
Tue May 27 10:03:39 PDT 2014


On Tue, May 27, 2014 at 10:49 AM, Christian König
<deathsimple at vodafone.de> wrote:
> From: Christian König <christian.koenig at amd.com>
>
> Instead of trying to flip inside the vblank period when
> the buffer is idle, offload blocking for idle to a kernel
> thread and program the flip directly into the hardware.
>
> v2: add error handling, fix EBUSY handling
> v3: add proper exclusive_lock handling
>
> Signed-off-by: Christian König <christian.koenig at amd.com>

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


> ---
>  drivers/gpu/drm/radeon/radeon.h         |  16 ++-
>  drivers/gpu/drm/radeon/radeon_display.c | 245 ++++++++++++++++++--------------
>  drivers/gpu/drm/radeon/radeon_mode.h    |   4 +-
>  3 files changed, 150 insertions(+), 115 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index 4ae304d..736bfa2 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -676,14 +676,16 @@ void radeon_doorbell_free(struct radeon_device *rdev, u32 doorbell);
>   * IRQS.
>   */
>
> -struct radeon_unpin_work {
> -       struct work_struct work;
> -       struct radeon_device *rdev;
> -       int crtc_id;
> -       struct radeon_fence *fence;
> +struct radeon_flip_work {
> +       struct work_struct              flip_work;
> +       struct work_struct              unpin_work;
> +       struct radeon_device            *rdev;
> +       int                             crtc_id;
> +       struct drm_framebuffer          *fb;
>         struct drm_pending_vblank_event *event;
> -       struct radeon_bo *old_rbo;
> -       u64 new_crtc_base;
> +       struct radeon_bo                *old_rbo;
> +       struct radeon_bo                *new_rbo;
> +       struct radeon_fence             *fence;
>  };
>
>  struct r500_irq_stat_regs {
> diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
> index 88e3cbe..6b3de5c 100644
> --- a/drivers/gpu/drm/radeon/radeon_display.c
> +++ b/drivers/gpu/drm/radeon/radeon_display.c
> @@ -249,16 +249,21 @@ static void radeon_crtc_destroy(struct drm_crtc *crtc)
>         struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
>
>         drm_crtc_cleanup(crtc);
> +       destroy_workqueue(radeon_crtc->flip_queue);
>         kfree(radeon_crtc);
>  }
>
> -/*
> - * Handle unpin events outside the interrupt handler proper.
> +/**
> + * radeon_unpin_work_func - unpin old buffer object
> + *
> + * @__work - kernel work item
> + *
> + * Unpin the old frame buffer object outside of the interrupt handler
>   */
>  static void radeon_unpin_work_func(struct work_struct *__work)
>  {
> -       struct radeon_unpin_work *work =
> -               container_of(__work, struct radeon_unpin_work, work);
> +       struct radeon_flip_work *work =
> +               container_of(__work, struct radeon_flip_work, unpin_work);
>         int r;
>
>         /* unpin of the old buffer */
> @@ -279,30 +284,19 @@ static void radeon_unpin_work_func(struct work_struct *__work)
>  void radeon_crtc_handle_vblank(struct radeon_device *rdev, int crtc_id)
>  {
>         struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[crtc_id];
> -       struct radeon_unpin_work *work;
> +       struct radeon_flip_work *work;
>         unsigned long flags;
>         u32 update_pending;
>         int vpos, hpos;
>
>         spin_lock_irqsave(&rdev->ddev->event_lock, flags);
> -       work = radeon_crtc->unpin_work;
> -       if (work == NULL ||
> -           (work->fence && !radeon_fence_signaled(work->fence))) {
> +       work = radeon_crtc->flip_work;
> +       if (work == NULL) {
>                 spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
>                 return;
>         }
> -       /* New pageflip, or just completion of a previous one? */
> -       if (!radeon_crtc->deferred_flip_completion) {
> -               /* do the flip (mmio) */
> -               radeon_page_flip(rdev, crtc_id, work->new_crtc_base);
> -               update_pending = radeon_page_flip_pending(rdev, crtc_id);
> -       } else {
> -               /* This is just a completion of a flip queued in crtc
> -                * at last invocation. Make sure we go directly to
> -                * completion routine.
> -                */
> -               update_pending = 0;
> -       }
> +
> +       update_pending = radeon_page_flip_pending(rdev, crtc_id);
>
>         /* Has the pageflip already completed in crtc, or is it certain
>          * to complete in this vblank?
> @@ -320,19 +314,9 @@ void radeon_crtc_handle_vblank(struct radeon_device *rdev, int crtc_id)
>                  */
>                 update_pending = 0;
>         }
> -       if (update_pending) {
> -               /* crtc didn't flip in this target vblank interval,
> -                * but flip is pending in crtc. It will complete it
> -                * in next vblank interval, so complete the flip at
> -                * next vblank irq.
> -                */
> -               radeon_crtc->deferred_flip_completion = 1;
> -               spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
> -               return;
> -       } else {
> -               spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
> +       spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
> +       if (!update_pending)
>                 radeon_crtc_handle_flip(rdev, crtc_id);
> -       }
>  }
>
>  /**
> @@ -346,7 +330,7 @@ void radeon_crtc_handle_vblank(struct radeon_device *rdev, int crtc_id)
>  void radeon_crtc_handle_flip(struct radeon_device *rdev, int crtc_id)
>  {
>         struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[crtc_id];
> -       struct radeon_unpin_work *work;
> +       struct radeon_flip_work *work;
>         unsigned long flags;
>
>         /* this can happen at init */
> @@ -354,15 +338,14 @@ void radeon_crtc_handle_flip(struct radeon_device *rdev, int crtc_id)
>                 return;
>
>         spin_lock_irqsave(&rdev->ddev->event_lock, flags);
> -       work = radeon_crtc->unpin_work;
> +       work = radeon_crtc->flip_work;
>         if (work == NULL) {
>                 spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
>                 return;
>         }
>
> -       /* Pageflip (will be) certainly completed in this vblank. Clean up. */
> -       radeon_crtc->unpin_work = NULL;
> -       radeon_crtc->deferred_flip_completion = 0;
> +       /* Pageflip completed. Clean up. */
> +       radeon_crtc->flip_work = NULL;
>
>         /* wakeup userspace */
>         if (work->event)
> @@ -372,83 +355,69 @@ void radeon_crtc_handle_flip(struct radeon_device *rdev, int crtc_id)
>
>         radeon_fence_unref(&work->fence);
>         radeon_irq_kms_pflip_irq_get(rdev, work->crtc_id);
> -       schedule_work(&work->work);
> +       queue_work(radeon_crtc->flip_queue, &work->unpin_work);
>  }
>
> -static int radeon_crtc_page_flip(struct drm_crtc *crtc,
> -                                struct drm_framebuffer *fb,
> -                                struct drm_pending_vblank_event *event,
> -                                uint32_t page_flip_flags)
> +/**
> + * radeon_flip_work_func - page flip framebuffer
> + *
> + * @work - kernel work item
> + *
> + * Wait for the buffer object to become idle and do the actual page flip
> + */
> +static void radeon_flip_work_func(struct work_struct *__work)
>  {
> -       struct drm_device *dev = crtc->dev;
> -       struct radeon_device *rdev = dev->dev_private;
> -       struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
> -       struct radeon_framebuffer *old_radeon_fb;
> -       struct radeon_framebuffer *new_radeon_fb;
> -       struct drm_gem_object *obj;
> -       struct radeon_bo *rbo;
> -       struct radeon_unpin_work *work;
> -       unsigned long flags;
> -       u32 tiling_flags, pitch_pixels;
> -       u64 base;
> -       int r;
> +       struct radeon_flip_work *work =
> +               container_of(__work, struct radeon_flip_work, flip_work);
> +       struct radeon_device *rdev = work->rdev;
> +       struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[work->crtc_id];
>
> -       work = kzalloc(sizeof *work, GFP_KERNEL);
> -       if (work == NULL)
> -               return -ENOMEM;
> +       struct drm_crtc *crtc = &radeon_crtc->base;
> +       struct drm_framebuffer *fb = work->fb;
>
> -       work->event = event;
> -       work->rdev = rdev;
> -       work->crtc_id = radeon_crtc->crtc_id;
> -       old_radeon_fb = to_radeon_framebuffer(crtc->primary->fb);
> -       new_radeon_fb = to_radeon_framebuffer(fb);
> -       /* schedule unpin of the old buffer */
> -       obj = old_radeon_fb->obj;
> -       /* take a reference to the old object */
> -       drm_gem_object_reference(obj);
> -       rbo = gem_to_radeon_bo(obj);
> -       work->old_rbo = rbo;
> -       obj = new_radeon_fb->obj;
> -       rbo = gem_to_radeon_bo(obj);
> +       uint32_t tiling_flags, pitch_pixels;
> +       uint64_t base;
>
> -       spin_lock(&rbo->tbo.bdev->fence_lock);
> -       if (rbo->tbo.sync_obj)
> -               work->fence = radeon_fence_ref(rbo->tbo.sync_obj);
> -       spin_unlock(&rbo->tbo.bdev->fence_lock);
> +       unsigned long flags;
> +       int r;
>
> -       INIT_WORK(&work->work, radeon_unpin_work_func);
> +        down_read(&rdev->exclusive_lock);
> +       while (work->fence) {
> +               r = radeon_fence_wait(work->fence, false);
> +               if (r == -EDEADLK) {
> +                       up_read(&rdev->exclusive_lock);
> +                       r = radeon_gpu_reset(rdev);
> +                       down_read(&rdev->exclusive_lock);
> +               }
>
> -       /* We borrow the event spin lock for protecting unpin_work */
> -       spin_lock_irqsave(&dev->event_lock, flags);
> -       if (radeon_crtc->unpin_work) {
> -               DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
> -               r = -EBUSY;
> -               goto unlock_free;
> +               if (r) {
> +                       DRM_ERROR("failed to wait on page flip fence (%d)!\n",
> +                                 r);
> +                       goto cleanup;
> +               } else
> +                       radeon_fence_unref(&work->fence);
>         }
> -       radeon_crtc->unpin_work = work;
> -       radeon_crtc->deferred_flip_completion = 0;
> -       spin_unlock_irqrestore(&dev->event_lock, flags);
>
>         /* pin the new buffer */
>         DRM_DEBUG_DRIVER("flip-ioctl() cur_fbo = %p, cur_bbo = %p\n",
> -                        work->old_rbo, rbo);
> +                        work->old_rbo, work->new_rbo);
>
> -       r = radeon_bo_reserve(rbo, false);
> +       r = radeon_bo_reserve(work->new_rbo, false);
>         if (unlikely(r != 0)) {
>                 DRM_ERROR("failed to reserve new rbo buffer before flip\n");
> -               goto pflip_cleanup;
> +               goto cleanup;
>         }
>         /* Only 27 bit offset for legacy CRTC */
> -       r = radeon_bo_pin_restricted(rbo, RADEON_GEM_DOMAIN_VRAM,
> +       r = radeon_bo_pin_restricted(work->new_rbo, RADEON_GEM_DOMAIN_VRAM,
>                                      ASIC_IS_AVIVO(rdev) ? 0 : 1 << 27, &base);
>         if (unlikely(r != 0)) {
> -               radeon_bo_unreserve(rbo);
> +               radeon_bo_unreserve(work->new_rbo);
>                 r = -EINVAL;
>                 DRM_ERROR("failed to pin new rbo buffer before flip\n");
> -               goto pflip_cleanup;
> +               goto cleanup;
>         }
> -       radeon_bo_get_tiling_flags(rbo, &tiling_flags, NULL);
> -       radeon_bo_unreserve(rbo);
> +       radeon_bo_get_tiling_flags(work->new_rbo, &tiling_flags, NULL);
> +       radeon_bo_unreserve(work->new_rbo);
>
>         if (!ASIC_IS_AVIVO(rdev)) {
>                 /* crtc offset is from display base addr not FB location */
> @@ -486,28 +455,91 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
>                 base &= ~7;
>         }
>
> -       spin_lock_irqsave(&dev->event_lock, flags);
> -       work->new_crtc_base = base;
> -       spin_unlock_irqrestore(&dev->event_lock, flags);
> -
> -       /* update crtc fb */
> -       crtc->primary->fb = fb;
> +       /* We borrow the event spin lock for protecting flip_work */
> +       spin_lock_irqsave(&crtc->dev->event_lock, flags);
>
>         /* set the proper interrupt */
>         radeon_irq_kms_pflip_irq_get(rdev, radeon_crtc->crtc_id);
>
> -       return 0;
> +       /* do the flip (mmio) */
> +       radeon_page_flip(rdev, radeon_crtc->crtc_id, base);
>
> -pflip_cleanup:
> -       spin_lock_irqsave(&dev->event_lock, flags);
> -       radeon_crtc->unpin_work = NULL;
> -unlock_free:
> -       spin_unlock_irqrestore(&dev->event_lock, flags);
> -       drm_gem_object_unreference_unlocked(old_radeon_fb->obj);
> +       spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> +       up_read(&rdev->exclusive_lock);
> +
> +       return;
> +
> +cleanup:
> +       drm_gem_object_unreference_unlocked(&work->old_rbo->gem_base);
>         radeon_fence_unref(&work->fence);
>         kfree(work);
> +       up_read(&rdev->exclusive_lock);
> +}
> +
> +static int radeon_crtc_page_flip(struct drm_crtc *crtc,
> +                                struct drm_framebuffer *fb,
> +                                struct drm_pending_vblank_event *event,
> +                                uint32_t page_flip_flags)
> +{
> +       struct drm_device *dev = crtc->dev;
> +       struct radeon_device *rdev = dev->dev_private;
> +       struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
> +       struct radeon_framebuffer *old_radeon_fb;
> +       struct radeon_framebuffer *new_radeon_fb;
> +       struct drm_gem_object *obj;
> +       struct radeon_flip_work *work;
> +       unsigned long flags;
> +
> +       work = kzalloc(sizeof *work, GFP_KERNEL);
> +       if (work == NULL)
> +               return -ENOMEM;
> +
> +       INIT_WORK(&work->flip_work, radeon_flip_work_func);
> +       INIT_WORK(&work->unpin_work, radeon_unpin_work_func);
>
> -       return r;
> +       work->rdev = rdev;
> +       work->crtc_id = radeon_crtc->crtc_id;
> +       work->fb = fb;
> +       work->event = event;
> +
> +       /* schedule unpin of the old buffer */
> +       old_radeon_fb = to_radeon_framebuffer(crtc->primary->fb);
> +       obj = old_radeon_fb->obj;
> +
> +       /* take a reference to the old object */
> +       drm_gem_object_reference(obj);
> +       work->old_rbo = gem_to_radeon_bo(obj);
> +
> +       new_radeon_fb = to_radeon_framebuffer(fb);
> +       obj = new_radeon_fb->obj;
> +       work->new_rbo = gem_to_radeon_bo(obj);
> +
> +       spin_lock(&work->new_rbo->tbo.bdev->fence_lock);
> +       if (work->new_rbo->tbo.sync_obj)
> +               work->fence = radeon_fence_ref(work->new_rbo->tbo.sync_obj);
> +       spin_unlock(&work->new_rbo->tbo.bdev->fence_lock);
> +
> +       /* update crtc fb */
> +       crtc->primary->fb = fb;
> +
> +       /* We borrow the event spin lock for protecting flip_work */
> +       spin_lock_irqsave(&crtc->dev->event_lock, flags);
> +
> +       if (radeon_crtc->flip_work) {
> +               DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
> +               spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> +               drm_gem_object_unreference_unlocked(&work->old_rbo->gem_base);
> +               radeon_fence_unref(&work->fence);
> +               kfree(work);
> +               return -EBUSY;
> +       }
> +       radeon_crtc->flip_work = work;
> +
> +       spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> +
> +       queue_work(radeon_crtc->flip_queue, &work->flip_work);
> +
> +       return 0;
>  }
>
>  static int
> @@ -577,6 +609,7 @@ static void radeon_crtc_init(struct drm_device *dev, int index)
>
>         drm_mode_crtc_set_gamma_size(&radeon_crtc->base, 256);
>         radeon_crtc->crtc_id = index;
> +       radeon_crtc->flip_queue = create_singlethread_workqueue("radeon-crtc");
>         rdev->mode_info.crtcs[index] = radeon_crtc;
>
>         if (rdev->family >= CHIP_BONAIRE) {
> diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
> index 718be1a..ea72ad8 100644
> --- a/drivers/gpu/drm/radeon/radeon_mode.h
> +++ b/drivers/gpu/drm/radeon/radeon_mode.h
> @@ -325,8 +325,8 @@ struct radeon_crtc {
>         struct drm_display_mode native_mode;
>         int pll_id;
>         /* page flipping */
> -       struct radeon_unpin_work *unpin_work;
> -       int deferred_flip_completion;
> +       struct workqueue_struct *flip_queue;
> +       struct radeon_flip_work *flip_work;
>         /* pll sharing */
>         struct radeon_atom_ss ss;
>         bool ss_enabled;
> --
> 1.9.1
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel


More information about the dri-devel mailing list