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Commit fd70075f authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
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drm/i915: Trim struct_mutex usage for kms 



Reduce acquisition of struct_mutex to the critical regions that must
hold it; for KMS, we need struct_mutex currently only for the purpose of
pinning/unpinning the framebuffer's VMA into the global GTT. This allows
us to avoid taking the struct_mutex when disabling the CRTC (i.e. NULL
framebuffer objects) before a reset. (Not yet achieving the full goal of
avoiding the strut_mutex nesting, but good enough to break the first
half of the reset deadlock.)

v2: Keep pages pinning inside struct_mutex for the moment.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170726160038.29487-1-chris@chris-wilson.co.uk


[danvet: Drop another case of grabbing dev->struct_mutex around
cleanup_planes, which popped up because I had to redo the drm-next
backmerge for entirely different reasons. Acked by Chris on irc.]
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent d38014ea

drivers/gpu/drm/i915/intel_display.c

+34 −48
Original line number Diff line number Diff line
@@ -11851,16 +11851,7 @@ static int intel_atomic_check(struct drm_device *dev, 
static int intel_atomic_prepare_commit(struct drm_device *dev,

				       struct drm_atomic_state *state)

{

	int ret;



	ret = mutex_lock_interruptible(&dev->struct_mutex);

	if (ret)

		return ret;



	ret = drm_atomic_helper_prepare_planes(dev, state);

	mutex_unlock(&dev->struct_mutex);



	return ret;

	return drm_atomic_helper_prepare_planes(dev, state);

}



u32 intel_crtc_get_vblank_counter(struct intel_crtc *crtc)
@@ -12223,9 +12214,7 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state) 
		intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET);

	}



	mutex_lock(&dev->struct_mutex);

	drm_atomic_helper_cleanup_planes(dev, state);

	mutex_unlock(&dev->struct_mutex);



	drm_atomic_helper_commit_cleanup_done(state);
@@ -12340,9 +12329,7 @@ static int intel_atomic_commit(struct drm_device *dev, 
	if (ret) {

		i915_sw_fence_commit(&intel_state->commit_ready);



		mutex_lock(&dev->struct_mutex);

		drm_atomic_helper_cleanup_planes(dev, state);

		mutex_unlock(&dev->struct_mutex);

		return ret;

	}

	dev_priv->wm.distrust_bios_wm = false;
@@ -12407,32 +12394,6 @@ intel_prepare_plane_fb(struct drm_plane *plane, 
	struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->state->fb);

	int ret;



	if (obj) {

		if (plane->type == DRM_PLANE_TYPE_CURSOR &&

		    INTEL_INFO(dev_priv)->cursor_needs_physical) {

			const int align = intel_cursor_alignment(dev_priv);



			ret = i915_gem_object_attach_phys(obj, align);

			if (ret) {

				DRM_DEBUG_KMS("failed to attach phys object\n");

				return ret;

			}

		} else {

			struct i915_vma *vma;



			vma = intel_pin_and_fence_fb_obj(fb, new_state->rotation);

			if (IS_ERR(vma)) {

				DRM_DEBUG_KMS("failed to pin object\n");

				return PTR_ERR(vma);

			}



			to_intel_plane_state(new_state)->vma = vma;

		}

	}



	if (!obj && !old_obj)

		return 0;



	if (old_obj) {

		struct drm_crtc_state *crtc_state =

			drm_atomic_get_existing_crtc_state(new_state->state,
@@ -12471,6 +12432,31 @@ intel_prepare_plane_fb(struct drm_plane *plane, 
	if (!obj)

		return 0;



	ret = mutex_lock_interruptible(&dev_priv->drm.struct_mutex);

	if (ret)

		return ret;



	if (plane->type == DRM_PLANE_TYPE_CURSOR &&

	    INTEL_INFO(dev_priv)->cursor_needs_physical) {

		const int align = intel_cursor_alignment(dev_priv);



		ret = i915_gem_object_attach_phys(obj, align);

	} else {

		struct i915_vma *vma;



		vma = intel_pin_and_fence_fb_obj(fb, new_state->rotation);

		if (!IS_ERR(vma))

			to_intel_plane_state(new_state)->vma = vma;

		else

			ret =  PTR_ERR(vma);

	}



	i915_gem_object_wait_priority(obj, 0, I915_PRIORITY_DISPLAY);



	mutex_unlock(&dev_priv->drm.struct_mutex);

	if (ret)

		return ret;



	if (!new_state->fence) { /* implicit fencing */

		ret = i915_sw_fence_await_reservation(&intel_state->commit_ready,

						      obj->resv, NULL,
@@ -12478,8 +12464,6 @@ intel_prepare_plane_fb(struct drm_plane *plane, 
						      GFP_KERNEL);

		if (ret < 0)

			return ret;



		i915_gem_object_wait_priority(obj, 0, I915_PRIORITY_DISPLAY);

	}



	return 0;
@@ -12502,8 +12486,11 @@ intel_cleanup_plane_fb(struct drm_plane *plane, 


	/* Should only be called after a successful intel_prepare_plane_fb()! */

	vma = fetch_and_zero(&to_intel_plane_state(old_state)->vma);

	if (vma)

	if (vma) {

		mutex_lock(&plane->dev->struct_mutex);

		intel_unpin_fb_vma(vma);

		mutex_unlock(&plane->dev->struct_mutex);

	}

}



int
@@ -12673,7 +12660,7 @@ intel_legacy_cursor_update(struct drm_plane *plane, 
	struct intel_plane *intel_plane = to_intel_plane(plane);

	struct drm_framebuffer *old_fb;

	struct drm_crtc_state *crtc_state = crtc->state;

	struct i915_vma *old_vma;

	struct i915_vma *old_vma, *vma;



	/*

	 * When crtc is inactive or there is a modeset pending,
@@ -12731,8 +12718,6 @@ intel_legacy_cursor_update(struct drm_plane *plane, 
			goto out_unlock;

		}

	} else {

		struct i915_vma *vma;



		vma = intel_pin_and_fence_fb_obj(fb, new_plane_state->rotation);

		if (IS_ERR(vma)) {

			DRM_DEBUG_KMS("failed to pin object\n");
@@ -12755,7 +12740,7 @@ intel_legacy_cursor_update(struct drm_plane *plane, 
	*to_intel_plane_state(old_plane_state) = *to_intel_plane_state(new_plane_state);

	new_plane_state->fence = NULL;

	new_plane_state->fb = old_fb;

	to_intel_plane_state(new_plane_state)->vma = old_vma;

	to_intel_plane_state(new_plane_state)->vma = NULL;



	if (plane->state->visible) {

		trace_intel_update_plane(plane, to_intel_crtc(crtc));
@@ -12767,7 +12752,8 @@ intel_legacy_cursor_update(struct drm_plane *plane, 
		intel_plane->disable_plane(intel_plane, to_intel_crtc(crtc));

	}



	intel_cleanup_plane_fb(plane, new_plane_state);

	if (old_vma)

		intel_unpin_fb_vma(old_vma);



out_unlock:

	mutex_unlock(&dev_priv->drm.struct_mutex);