drm/i915: add the FBC mutex
Make sure we're not going to have weird races in really weird cases
where a lot of different CRTCs are doing rendering and modesets at the
same time.
With this change and the stolen_lock from the previous patch, we can
start removing the struct_mutex locking we have around FBC in the next
patches.
v2:
- Rebase (6 months later)
- Also lock debugfs and stolen.
v3:
- Don't lock a single value read (Chris).
- Replace lockdep assertions with WARNs (Daniel).
- Improve commit message.
- Don't forget intel_pre_plane_update() locking.
v4:
- Don't remove struct_mutex at intel_pre_plane_update() (Chris).
- Add comment regarding locking dependencies (Chris).
- Rebase after the stolen code rework.
- Rebase again after drm-intel-nightly changes.
v5:
- Rebase after the new stolen_lock patch.
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v4)
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 6a8de04..cc74a92 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1633,6 +1633,7 @@
}
intel_runtime_pm_get(dev_priv);
+ mutex_lock(&dev_priv->fbc.lock);
if (intel_fbc_enabled(dev))
seq_puts(m, "FBC enabled\n");
@@ -1645,6 +1646,7 @@
yesno(I915_READ(FBC_STATUS2) &
FBC_COMPRESSION_MASK));
+ mutex_unlock(&dev_priv->fbc.lock);
intel_runtime_pm_put(dev_priv);
return 0;
@@ -1675,6 +1677,7 @@
return -ENODEV;
drm_modeset_lock_all(dev);
+ mutex_lock(&dev_priv->fbc.lock);
reg = I915_READ(ILK_DPFC_CONTROL);
dev_priv->fbc.false_color = val;
@@ -1683,6 +1686,7 @@
(reg | FBC_CTL_FALSE_COLOR) :
(reg & ~FBC_CTL_FALSE_COLOR));
+ mutex_unlock(&dev_priv->fbc.lock);
drm_modeset_unlock_all(dev);
return 0;
}