We don't have any read in a fastpath that needs forcewake, so I've decided to not care much about overhead.
This prevents tests/gem_hangcheck_forcewake from i-g-t from killing my snb on recent kernels - something must have slightly changed the timings. Signed-Off-by: Daniel Vetter <[email protected]> --- drivers/gpu/drm/i915/i915_debugfs.c | 8 ++++++-- drivers/gpu/drm/i915/i915_drv.c | 19 +++++++++++++------ drivers/gpu/drm/i915/i915_drv.h | 3 ++- 3 files changed, 21 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 5ba63ad..51b21eb 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -1320,9 +1320,13 @@ static int i915_gen6_forcewake_count_info(struct seq_file *m, void *data) struct drm_info_node *node = (struct drm_info_node *) m->private; struct drm_device *dev = node->minor->dev; struct drm_i915_private *dev_priv = dev->dev_private; + unsigned forcewake_count; - seq_printf(m, "forcewake count = %d\n", - atomic_read(&dev_priv->forcewake_count)); + spin_lock_irq(&dev_priv->gt_lock); + forcewake_count = dev_priv->forcewake_count; + spin_unlock_irq(&dev_priv->gt_lock); + + seq_printf(m, "forcewake count = %d\n", forcewake_count); return 0; } diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index cefc3b9..14753f5 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -351,11 +351,12 @@ static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv) */ void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv) { - WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex)); + unsigned long irqflags; - /* Forcewake is atomic in case we get in here without the lock */ - if (atomic_add_return(1, &dev_priv->forcewake_count) == 1) + spin_lock_irqsave(&dev_priv->gt_lock, irqflags); + if (dev_priv->forcewake_count++ == 0) __gen6_gt_force_wake_get(dev_priv); + spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); } static void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv) @@ -369,10 +370,13 @@ static void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv) */ void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv) { - WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex)); + unsigned long irqflags; + + spin_lock_irqsave(&dev_priv->gt_lock, irqflags); - if (atomic_dec_and_test(&dev_priv->forcewake_count)) + if (--dev_priv->forcewake_count == 0) __gen6_gt_force_wake_put(dev_priv); + spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); } void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv) @@ -615,6 +619,7 @@ int i915_reset(struct drm_device *dev, u8 flags) * need to */ bool need_display = true; + unsigned long irqflags; int ret; if (!i915_try_reset) @@ -633,8 +638,10 @@ int i915_reset(struct drm_device *dev, u8 flags) case 6: ret = gen6_do_reset(dev, flags); /* If reset with a user forcewake, try to restore */ - if (atomic_read(&dev_priv->forcewake_count)) + spin_lock_irqsave(&dev_priv->gt_lock, irqflags); + if (dev_priv->forcewake_count) __gen6_gt_force_wake_get(dev_priv); + spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); break; case 5: ret = ironlake_do_reset(dev, flags); diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 74cf78e..cbac640 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -278,7 +278,8 @@ typedef struct drm_i915_private { void __iomem *regs; /** Concurrent writes to gt_fifo_count are protected by gt_lock */ atomic_t gt_fifo_count; - atomic_t forcewake_count; + /** forcewake_count is protected by gt_lock */ + unsigned forcewake_count; /** gt_lock is taking in irq contexts. */ struct spinlock gt_lock; -- 1.7.6.4 _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
