drm/i915: Wait for all pending operations to the fb before disabling the pipe
authorChris Wilson <chris@chris-wilson.co.uk>
Tue, 17 Apr 2012 09:05:38 +0000 (10:05 +0100)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Wed, 18 Apr 2012 10:59:24 +0000 (12:59 +0200)
During modeset we have to disable the pipe to reconfigure its timings
and maybe its size. Userspace may have queued up command buffers that
depend upon the pipe running in a certain configuration and so the
commands may become confused across the modeset. At the moment, we use a
less than satisfactory kick-scanline-waits should the GPU hang during
the modeset. It should be more reliable to wait for the pending
operations to complete first, even though we still have a window for
userspace to submit a broken command buffer during the modeset.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/intel_display.c

index a1a808047f12b5286a213d5128105d2f5dc0e28d..39eb3e8bf1bc841cbf1be5a782a70275a9a82a5d 100644 (file)
@@ -3014,16 +3014,14 @@ static void intel_clear_scanline_wait(struct drm_device *dev)
 
 static void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
 {
-       struct drm_i915_gem_object *obj;
-       struct drm_i915_private *dev_priv;
+       struct drm_device *dev = crtc->dev;
 
        if (crtc->fb == NULL)
                return;
 
-       obj = to_intel_framebuffer(crtc->fb)->obj;
-       dev_priv = crtc->dev->dev_private;
-       wait_event(dev_priv->pending_flip_queue,
-                  atomic_read(&obj->pending_flip) == 0);
+       mutex_lock(&dev->struct_mutex);
+       intel_finish_fb(crtc->fb);
+       mutex_unlock(&dev->struct_mutex);
 }
 
 static bool intel_crtc_driving_pch(struct drm_crtc *crtc)
@@ -3485,23 +3483,6 @@ static void intel_crtc_disable(struct drm_crtc *crtc)
        struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
        struct drm_device *dev = crtc->dev;
 
-       /* Flush any pending WAITs before we disable the pipe. Note that
-        * we need to drop the struct_mutex in order to acquire it again
-        * during the lowlevel dpms routines around a couple of the
-        * operations. It does not look trivial nor desirable to move
-        * that locking higher. So instead we leave a window for the
-        * submission of further commands on the fb before we can actually
-        * disable it. This race with userspace exists anyway, and we can
-        * only rely on the pipe being disabled by userspace after it
-        * receives the hotplug notification and has flushed any pending
-        * batches.
-        */
-       if (crtc->fb) {
-               mutex_lock(&dev->struct_mutex);
-               intel_finish_fb(crtc->fb);
-               mutex_unlock(&dev->struct_mutex);
-       }
-
        crtc_funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
        assert_plane_disabled(dev->dev_private, to_intel_crtc(crtc)->plane);
        assert_pipe_disabled(dev->dev_private, to_intel_crtc(crtc)->pipe);