@@ -1247,23 +1247,23 @@ ilk_dummy_write(struct drm_i915_private *dev_priv)
#define __i915_read(x, y) \
u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
+ unsigned long irqflags; \
u##x val = 0; \
+ spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \
if (IS_GEN5(dev_priv->dev)) \
ilk_dummy_write(dev_priv); \
if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
- unsigned long irqflags; \
- spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \
if (dev_priv->forcewake_count == 0) \
dev_priv->gt.force_wake_get(dev_priv); \
val = read##y(dev_priv->regs + reg); \
if (dev_priv->forcewake_count == 0) \
dev_priv->gt.force_wake_put(dev_priv); \
- spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); \
} else if (IS_VALLEYVIEW(dev_priv->dev) && IS_DISPLAYREG(reg)) { \
val = read##y(dev_priv->regs + reg + 0x180000); \
} else { \
val = read##y(dev_priv->regs + reg); \
} \
+ spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); \
trace_i915_reg_rw(false, reg, val, sizeof(val)); \
return val; \
}
@@ -1276,8 +1276,10 @@ __i915_read(64, q)
#define __i915_write(x, y) \
void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
+ unsigned long irqflags; \
u32 __fifo_ret = 0; \
trace_i915_reg_rw(true, reg, val, sizeof(val)); \
+ spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \
if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
__fifo_ret = __gen6_gt_wait_for_fifo(dev_priv); \
} \
@@ -1299,6 +1301,7 @@ void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
DRM_ERROR("Unclaimed write to %x\n", reg); \
writel(ERR_INT_MMIO_UNCLAIMED, dev_priv->regs + GEN7_ERR_INT); \
} \
+ spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); \
}
__i915_write(8, b)
__i915_write(16, w)
This is a note to let you know that I have just added a patch titled drm/i915: Serialize almost all register access to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.6. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 4dda4ec438e3e43de4db14195fa7f413394d17d8 Mon Sep 17 00:00:00 2001 From: Chris Wilson <chris@chris-wilson.co.uk> Date: Fri, 19 Jul 2013 20:36:51 +0100 Subject: drm/i915: Serialize almost all register access commit a7cd1b8fea2f341b626b255d9898a5ca5fabbf0a upstream. In theory, the different register blocks were meant to be only ever touched when holding either the struct_mutex, mode_config.lock or even a specific localised lock. This does not seem to be the case, and the hardware reacts extremely badly if we attempt to concurrently access two registers within the same cacheline. The HSD suggests that we only need to do this workaround for display range registers. However, upon review we need to serialize the multiple stages in our register write functions - if only for preemption protection. Irrespective of the hardware requirements, the current io functions are a little too loose with respect to the combination of pre- and post-condition testing that we do in conjunction with the actual io. As a result, we may be pre-empted and generate both false-postive and false-negative errors. Note well that this is a "90%" solution, there remains a few direct users of ioread/iowrite which will be fixed up in the next few patches. Since they are more invasive and that this simple change will prevent almost all lockups on Haswell, we kept this patch simple to facilitate backporting to stable. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=63914 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> [ kamal: backport to 3.8 ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/gpu/drm/i915/i915_drv.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) -- 1.8.1.2