[PATCH] drm/i915: Move drm_framebuffer_unreference out of struct_mutex for takeover

Tvrtko Ursulin
2015-04-13T15:03:39Z

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

intel_user_framebuffer_destroy() requires the struct_mutex for its
object bookkeeping, so this means that all calls to
drm_framebuffer_unreference must be held without that lock.

This is a simplified version of the identically named patch by Chris Wilson.

Regression from commit ab8d66752a9c28cd6c94fa173feacdfc1554aa03
Author: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Date: Mon Feb 2 15:44:15 2015 +0000

drm/i915: Track old framebuffer instead of object

v2: Bikeshedding.

References: https://bugs.freedesktop.org/show_bug.cgi?id=89166
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 97922fb..5fb11bc 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -14739,6 +14739,7 @@ void intel_modeset_gem_init(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_crtc *c;
struct drm_i915_gem_object *obj;
+ int ret;

mutex_lock(&dev->struct_mutex);
intel_init_gt_powersave(dev);
@@ -14763,16 +14764,18 @@ void intel_modeset_gem_init(struct drm_device *dev)
* pinned & fenced. When we do the allocation it's too early
* for this.
*/
- mutex_lock(&dev->struct_mutex);
for_each_crtc(dev, c) {
obj = intel_fb_obj(c->primary->fb);
if (obj == NULL)
continue;

- if (intel_pin_and_fence_fb_obj(c->primary,
- c->primary->fb,
- c->primary->state,
- NULL)) {
+ mutex_lock(&dev->struct_mutex);
+ ret = intel_pin_and_fence_fb_obj(c->primary,
+ c->primary->fb,
+ c->primary->state,
+ NULL);
+ mutex_unlock(&dev->struct_mutex);
+ if (ret) {
DRM_ERROR("failed to pin boot fb on pipe %d\n",
to_intel_crtc(c)->pipe);
drm_framebuffer_unreference(c->primary->fb);
@@ -14780,7 +14783,6 @@ void intel_modeset_gem_init(struct drm_device *dev)
update_state_fb(c->primary);
}
}
- mutex_unlock(&dev->struct_mutex);

intel_backlight_register(dev);
}
--
2.3.5