drm/i915: fix ilk rc6 teardown locking
In the failure cases during rc6 initialization, both the power context
and render context may get !refcount without holding struct_mutex.
However, on rc6 disabling, the lock is held by the caller.
Rearranged the locking so that it's safe in both cases.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index bcef1c1..b6f593a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6713,13 +6713,14 @@
struct drm_i915_gem_object *ctx;
int ret;
+ WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+
ctx = i915_gem_alloc_object(dev, 4096);
if (!ctx) {
DRM_DEBUG("failed to alloc power context, RC6 disabled\n");
return NULL;
}
- mutex_lock(&dev->struct_mutex);
ret = i915_gem_object_pin(ctx, 4096, true);
if (ret) {
DRM_ERROR("failed to pin power context: %d\n", ret);
@@ -6731,7 +6732,6 @@
DRM_ERROR("failed to set-domain on power context: %d\n", ret);
goto err_unpin;
}
- mutex_unlock(&dev->struct_mutex);
return ctx;
@@ -7295,9 +7295,12 @@
if (!i915_enable_rc6)
return;
+ mutex_lock(&dev->struct_mutex);
ret = ironlake_setup_rc6(dev);
- if (ret)
+ if (ret) {
+ mutex_unlock(&dev->struct_mutex);
return;
+ }
/*
* GPU can automatically power down the render unit if given a page
@@ -7306,6 +7309,7 @@
ret = BEGIN_LP_RING(6);
if (ret) {
ironlake_teardown_rc6(dev);
+ mutex_unlock(&dev->struct_mutex);
return;
}
@@ -7323,6 +7327,7 @@
I915_WRITE(PWRCTXA, dev_priv->pwrctx->gtt_offset | PWRCTX_EN);
I915_WRITE(RSTDBYCTL, I915_READ(RSTDBYCTL) & ~RCX_SW_EXIT);
+ mutex_unlock(&dev->struct_mutex);
}