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Commit f935675f authored by Maarten Lankhorst's avatar Maarten Lankhorst
Browse files

drm/i915: Change locking for struct_mutex, v3. 



struct_mutex is being locked for every plane in intel_prepare_plane_fb
and intel_cleanup_plane_fb.

Require the caller to hold the mutex, and only acquire the mutex for
each helper call. This way the lock only needs to be acquired
twice in ->atomic_commit(). Once for pinning new framebuffers at the
start, the second time for unpinning old framebuffer.

Changes since v1:
- Use mutex_lock_interruptible instead of i915 variant,
  to prevent a deadlock when called from the reset code.
Changes since v2:
- Clarify struct_mutex is locked by the caller.

Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com> #v1
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent 5008e874

drivers/gpu/drm/i915/intel_display.c

+13 −10
Original line number Original line Diff line number Diff line
@@ -13165,8 +13165,13 @@ static int intel_atomic_prepare_commit(struct drm_device *dev, 
			return ret;

			return ret;

	}

	}





	ret = mutex_lock_interruptible(&dev->struct_mutex);

	if (ret)

		return ret;



	ret = drm_atomic_helper_prepare_planes(dev, state);

	ret = drm_atomic_helper_prepare_planes(dev, state);





	mutex_unlock(&dev->struct_mutex);

	return ret;

	return ret;

}

}
@@ -13268,7 +13273,10 @@ static int intel_atomic_commit(struct drm_device *dev, 
	/* FIXME: add subpixel order */

	/* FIXME: add subpixel order */





	drm_atomic_helper_wait_for_vblanks(dev, state);

	drm_atomic_helper_wait_for_vblanks(dev, state);



	mutex_lock(&dev->struct_mutex);

	drm_atomic_helper_cleanup_planes(dev, state);

	drm_atomic_helper_cleanup_planes(dev, state);

	mutex_unlock(&dev->struct_mutex);





	if (any_ms)

	if (any_ms)

		intel_modeset_check_state(dev, state);

		intel_modeset_check_state(dev, state);
@@ -13437,6 +13445,8 @@ static void intel_shared_dpll_init(struct drm_device *dev) 
 * bits.  Some older platforms need special physical address handling for

 * bits.  Some older platforms need special physical address handling for

 * cursor planes.

 * cursor planes.

 *

 *

 * Must be called with struct_mutex held.

 *

 * Returns 0 on success, negative error code on failure.

 * Returns 0 on success, negative error code on failure.

 */

 */

int

int
@@ -13453,10 +13463,6 @@ intel_prepare_plane_fb(struct drm_plane *plane, 
	if (!obj && !old_obj)

	if (!obj && !old_obj)

		return 0;

		return 0;





	ret = i915_mutex_lock_interruptible(dev);

	if (ret)

		return ret;



	if (old_obj) {

	if (old_obj) {

		struct drm_crtc_state *crtc_state =

		struct drm_crtc_state *crtc_state =

			drm_atomic_get_existing_crtc_state(new_state->state, plane->state->crtc);

			drm_atomic_get_existing_crtc_state(new_state->state, plane->state->crtc);
@@ -13477,7 +13483,7 @@ intel_prepare_plane_fb(struct drm_plane *plane, 




		/* Swallow -EIO errors to allow updates during hw lockup. */

		/* Swallow -EIO errors to allow updates during hw lockup. */

		if (ret && ret != -EIO)

		if (ret && ret != -EIO)

			goto out;

			return ret;

	}

	}





	if (!obj) {

	if (!obj) {
@@ -13495,9 +13501,6 @@ intel_prepare_plane_fb(struct drm_plane *plane, 
	if (ret == 0)

	if (ret == 0)

		i915_gem_track_fb(old_obj, obj, intel_plane->frontbuffer_bit);

		i915_gem_track_fb(old_obj, obj, intel_plane->frontbuffer_bit);





out:

	mutex_unlock(&dev->struct_mutex);



	return ret;

	return ret;

}

}
@@ -13507,6 +13510,8 @@ intel_prepare_plane_fb(struct drm_plane *plane, 
 * @fb: old framebuffer that was on plane

 * @fb: old framebuffer that was on plane

 *

 *

 * Cleans up a framebuffer that has just been removed from a plane.

 * Cleans up a framebuffer that has just been removed from a plane.

 *

 * Must be called with struct_mutex held.

 */

 */

void

void

intel_cleanup_plane_fb(struct drm_plane *plane,

intel_cleanup_plane_fb(struct drm_plane *plane,
@@ -13520,7 +13525,6 @@ intel_cleanup_plane_fb(struct drm_plane *plane, 
	if (!obj && !old_obj)

	if (!obj && !old_obj)

		return;

		return;





	mutex_lock(&dev->struct_mutex);

	if (old_obj && (plane->type != DRM_PLANE_TYPE_CURSOR ||

	if (old_obj && (plane->type != DRM_PLANE_TYPE_CURSOR ||

	    !INTEL_INFO(dev)->cursor_needs_physical))

	    !INTEL_INFO(dev)->cursor_needs_physical))

		intel_unpin_fb_obj(old_state->fb, old_state);

		intel_unpin_fb_obj(old_state->fb, old_state);
@@ -13529,7 +13533,6 @@ intel_cleanup_plane_fb(struct drm_plane *plane, 
	if ((old_obj && (old_obj->frontbuffer_bits & intel_plane->frontbuffer_bit)) ||

	if ((old_obj && (old_obj->frontbuffer_bits & intel_plane->frontbuffer_bit)) ||

	    (obj && !(obj->frontbuffer_bits & intel_plane->frontbuffer_bit)))

	    (obj && !(obj->frontbuffer_bits & intel_plane->frontbuffer_bit)))

		i915_gem_track_fb(old_obj, obj, intel_plane->frontbuffer_bit);

		i915_gem_track_fb(old_obj, obj, intel_plane->frontbuffer_bit);

	mutex_unlock(&dev->struct_mutex);

}

}





int

int