From c937504e2b96af3b281b1ef859e063ef4af656c1 Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Fri, 6 Jan 2012 11:48:38 -0800 Subject: [PATCH] drm/i915: Hold gt_lock across forcewake register reads Along with the previous patch to make the reset operation protected by the gt_lock as well, this ensures that all register read operations will occur with the forcewake hardware enabled. As an added bonus, this makes read operations more efficient by taking the spinlock only once per read instead of twice. Signed-off-by: Keith Packard Reviewed-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 062d1d2..308f819 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -954,9 +954,14 @@ MODULE_LICENSE("GPL and additional rights"); u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \ u##x val = 0; \ if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \ - gen6_gt_force_wake_get(dev_priv); \ + unsigned long irqflags; \ + spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \ + if (dev_priv->forcewake_count == 0) \ + dev_priv->display.force_wake_get(dev_priv); \ val = read##y(dev_priv->regs + reg); \ - gen6_gt_force_wake_put(dev_priv); \ + if (dev_priv->forcewake_count == 0) \ + dev_priv->display.force_wake_put(dev_priv); \ + spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); \ } else { \ val = read##y(dev_priv->regs + reg); \ } \ -- 2.7.4