drm/i915: Make dev_priv->mm.wedged an atomic_t
There is a very real possibility that multiple CPUs will notice that the
GPU is wedged. This introduces all sorts of potential race conditions.
Make the wedged flag atomic to mitigate this risk.
Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 8f52766..13e664d 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -309,12 +309,12 @@
DRM_DEBUG("generating error event\n");
kobject_uevent_env(&dev->primary->kdev.kobj, KOBJ_CHANGE, error_event);
- if (dev_priv->mm.wedged) {
+ if (atomic_read(&dev_priv->mm.wedged)) {
if (IS_I965G(dev)) {
DRM_DEBUG("resetting chip\n");
kobject_uevent_env(&dev->primary->kdev.kobj, KOBJ_CHANGE, reset_event);
if (!i965_reset(dev, GDRST_RENDER)) {
- dev_priv->mm.wedged = 0;
+ atomic_set(&dev_priv->mm.wedged, 0);
kobject_uevent_env(&dev->primary->kdev.kobj, KOBJ_CHANGE, reset_done_event);
}
} else {
@@ -385,7 +385,7 @@
* so userspace knows something bad happened (should trigger collection
* of a ring dump etc.).
*/
-static void i915_handle_error(struct drm_device *dev)
+static void i915_handle_error(struct drm_device *dev, bool wedged)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u32 eir = I915_READ(EIR);
@@ -495,7 +495,9 @@
I915_WRITE(IIR, I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT);
}
- if (dev_priv->mm.wedged) {
+ if (wedged) {
+ atomic_set(&dev_priv->mm.wedged, 1);
+
/*
* Wakeup waiting processes so they don't hang
*/
@@ -548,7 +550,7 @@
pipeb_stats = I915_READ(PIPEBSTAT);
if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
- i915_handle_error(dev);
+ i915_handle_error(dev, false);
/*
* Clear the PIPE(A|B)STAT regs before the IIR
@@ -934,8 +936,7 @@
if (dev_priv->last_acthd == acthd && dev_priv->hangcheck_count > 0) {
DRM_ERROR("Hangcheck timer elapsed... GPU hung\n");
- dev_priv->mm.wedged = true; /* Hopefully this is atomic */
- i915_handle_error(dev);
+ i915_handle_error(dev, true);
return;
}