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 at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/intel_display.c | 27 ++++-----------------------
1 file changed, 4 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8be3091..72980be 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2910,16 +2910,14 @@ 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)
@@ -3381,23 +3379,6 @@ 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);
--
1.7.10
