From b3f5e7329df1a508ac58ebe7509fb7a47b9eab6a Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 19 Feb 2009 14:48:22 +0000 Subject: [PATCH] drm: Correct unbalanced drm_vblank_put() during mode setting. The first time we install a mode, the vblank will be disabled for a pipe and so drm_vblank_get() in drm_vblank_pre_modeset() will fail. As we unconditionally call drm_vblank_put() afterwards, the vblank reference counter becomes unbalanced. Signed-off-by: Chris Wilson Acked-by: Jesse Barnes Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_irq.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 3795dbc0f50..93e677a481f 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -435,6 +435,8 @@ EXPORT_SYMBOL(drm_vblank_get); */ void drm_vblank_put(struct drm_device *dev, int crtc) { + BUG_ON (atomic_read (&dev->vblank_refcount[crtc]) == 0); + /* Last user schedules interrupt disable */ if (atomic_dec_and_test(&dev->vblank_refcount[crtc])) mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ); @@ -460,8 +462,9 @@ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) * so that interrupts remain enabled in the interim. */ if (!dev->vblank_inmodeset[crtc]) { - dev->vblank_inmodeset[crtc] = 1; - drm_vblank_get(dev, crtc); + dev->vblank_inmodeset[crtc] = 0x1; + if (drm_vblank_get(dev, crtc) == 0) + dev->vblank_inmodeset[crtc] |= 0x2; } } EXPORT_SYMBOL(drm_vblank_pre_modeset); @@ -473,9 +476,12 @@ void drm_vblank_post_modeset(struct drm_device *dev, int crtc) if (dev->vblank_inmodeset[crtc]) { spin_lock_irqsave(&dev->vbl_lock, irqflags); dev->vblank_disable_allowed = 1; - dev->vblank_inmodeset[crtc] = 0; spin_unlock_irqrestore(&dev->vbl_lock, irqflags); - drm_vblank_put(dev, crtc); + + if (dev->vblank_inmodeset[crtc] & 0x2) + drm_vblank_put(dev, crtc); + + dev->vblank_inmodeset[crtc] = 0; } } EXPORT_SYMBOL(drm_vblank_post_modeset); -- 2.41.0