From: Keith Packard Date: Fri, 6 Jan 2012 19:48:38 +0000 (-0800) Subject: drm/i915: Hold gt_lock across forcewake register reads X-Git-Tag: v3.3-rc2~20^2~3^2~8 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=c937504e2b96af3b281b1ef859e063ef4af656c1;p=~emulex%2Finfiniband.git 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 --- diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 062d1d27f70..308f8191356 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); \ } \