Re: [PATCH v2] drm/radeon: Track the status of a page flip more explicitly

On Mon, Jun 30, 2014 at 5:12 AM, Michel Dänzer michel@daenzer.net wrote:

From: Michel Dänzer michel.daenzer@amd.com

This prevents a panic: radeon_crtc_handle_page_flip() could run before radeon_flip_work_func(), triggering the BUG_ON() in drm_vblank_put().

Tested-by: Dieter Nützel Dieter@nuetzel-hh.de Signed-off-by: Michel Dänzer michel.daenzer@amd.com

---

v2: Update log message

Applied to to by -fixes tree.

Alex

drivers/gpu/drm/radeon/radeon_display.c | 19 ++++++++++++++----- drivers/gpu/drm/radeon/radeon_mode.h | 7 +++++++ 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c index 8b575a4..65882cd 100644 --- a/drivers/gpu/drm/radeon/radeon_display.c +++ b/drivers/gpu/drm/radeon/radeon_display.c @@ -284,7 +284,6 @@ 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_flip_work *work;
    unsigned long flags;
    u32 update_pending;
    int vpos, hpos;
  

@@ -294,8 +293,11 @@ void radeon_crtc_handle_vblank(struct radeon_device *rdev, int crtc_id) return;

    spin_lock_irqsave(&rdev->ddev->event_lock, flags);

•   work = radeon_crtc->flip_work;
  

•   if (work == NULL) {
  

•   if (radeon_crtc->flip_status != RADEON_FLIP_SUBMITTED) {
  

•           DRM_DEBUG_DRIVER("radeon_crtc->flip_status = %d != "
  

•                            "RADEON_FLIP_SUBMITTED(%d)\n",
  

•                            radeon_crtc->flip_status,
  

•                            RADEON_FLIP_SUBMITTED);
            spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
            return;
    }
  

@@ -343,12 +345,17 @@ void radeon_crtc_handle_flip(struct radeon_device *rdev, int crtc_id)

    spin_lock_irqsave(&rdev->ddev->event_lock, flags);
    work = radeon_crtc->flip_work;

•   if (work == NULL) {
  

•   if (radeon_crtc->flip_status != RADEON_FLIP_SUBMITTED) {
  

•           DRM_DEBUG_DRIVER("radeon_crtc->flip_status = %d != "
  

•                            "RADEON_FLIP_SUBMITTED(%d)\n",
  

•                            radeon_crtc->flip_status,
  

•                            RADEON_FLIP_SUBMITTED);
            spin_unlock_irqrestore(&rdev->ddev->event_lock, flags);
            return;
    }
  
    /* Pageflip completed. Clean up. */
  

•   radeon_crtc->flip_status = RADEON_FLIP_NONE;
    radeon_crtc->flip_work = NULL;
  
    /* wakeup userspace */
  

@@ -475,6 +482,7 @@ static void radeon_flip_work_func(struct work_struct *__work) /* do the flip (mmio) */ radeon_page_flip(rdev, radeon_crtc->crtc_id, base);

•   radeon_crtc->flip_status = RADEON_FLIP_SUBMITTED;
    spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
    up_read(&rdev->exclusive_lock);
  
  

@@ -543,7 +551,7 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc, /* We borrow the event spin lock for protecting flip_work */ spin_lock_irqsave(&crtc->dev->event_lock, flags);

•   if (radeon_crtc->flip_work) {
  

•   if (radeon_crtc->flip_status != RADEON_FLIP_NONE) {
            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);
  

@@ -551,6 +559,7 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc, kfree(work); return -EBUSY; }

•   radeon_crtc->flip_status = RADEON_FLIP_PENDING;
    radeon_crtc->flip_work = work;
  
    /* update crtc fb */
  

diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h index b59096f..ed6b6e0 100644 --- a/drivers/gpu/drm/radeon/radeon_mode.h +++ b/drivers/gpu/drm/radeon/radeon_mode.h @@ -301,6 +301,12 @@ struct radeon_atom_ss { uint16_t amount; };

+enum radeon_flip_status {

•   RADEON_FLIP_NONE,
  

•   RADEON_FLIP_PENDING,
  

•   RADEON_FLIP_SUBMITTED
  

+};

struct radeon_crtc { struct drm_crtc base; int crtc_id; @@ -326,6 +332,7 @@ struct radeon_crtc { /* page flipping */ struct workqueue_struct *flip_queue; struct radeon_flip_work *flip_work;

•   enum radeon_flip_status flip_status;
    /* pll sharing */
    struct radeon_atom_ss ss;
    bool ss_enabled;
  

-- 2.0.0

---

dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel