From 286fed412a134e76be55899bc628c6fa59cb70da Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Fri, 6 Jan 2012 11:44:11 -0800 Subject: [PATCH] drm/i915: Hold gt_lock during reset This ensures that no register reads occur while the forcewake state of the hardware is indeterminate during the reset operation. Signed-off-by: Keith Packard Reviewed-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index a6fcd941e3ab..062d1d27f704 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -603,12 +603,31 @@ static int gen6_do_reset(struct drm_device *dev, u8 flags) int ret; unsigned long irqflags; - I915_WRITE(GEN6_GDRST, GEN6_GRDOM_FULL); - ret = wait_for((I915_READ(GEN6_GDRST) & GEN6_GRDOM_FULL) == 0, 500); - /* If reset with a user forcewake, try to restore */ + /* Hold gt_lock across reset to prevent any register access + * with forcewake not set correctly + */ spin_lock_irqsave(&dev_priv->gt_lock, irqflags); + + /* Reset the chip */ + + /* GEN6_GDRST is not in the gt power well, no need to check + * for fifo space for the write or forcewake the chip for + * the read + */ + I915_WRITE_NOTRACE(GEN6_GDRST, GEN6_GRDOM_FULL); + + /* Spin waiting for the device to ack the reset request */ + ret = wait_for((I915_READ_NOTRACE(GEN6_GDRST) & GEN6_GRDOM_FULL) == 0, 500); + + /* If reset with a user forcewake, try to restore, otherwise turn it off */ if (dev_priv->forcewake_count) dev_priv->display.force_wake_get(dev_priv); + else + dev_priv->display.force_wake_put(dev_priv); + + /* Restore fifo count */ + dev_priv->gt_fifo_count = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); return ret; } -- 2.39.5