In trying to use the drm_hwcomposer on HiKey, I found things
wouldn't initialize due to the following check in
drm_atomic_crtc_check() failing:
if (state->event && !state->active && !crtc->state->active) {
DRM_DEBUG_ATOMIC("[CRTC:%d:%s] requesting event but off\n",
crtc->base.id, crtc->name);
return -EINVAL;
}
This case fails because the crtc_state hasn't been set to active
yet.
However, this trips on the first call to drm_atomic_commit(),
where the drm_hwcomposer is trying to setup the initial mode.
Digging further its seems the state->event value is set because
before we get into handling the atomic mode, we call
prepare_crtc_signaling(), which sees a fence ptr, and calls
create_vblank_event().
So to hack around this, I've added a check in
prepare_crtc_signaling() to see if the crtc_state is active and
if not, skip trying to create the vblank event.
I suspect this isn't correct, but I'm a bit confused on what the
right solution is. I was thinking the drm_hwcomposer was missing
something to enable the display before calling
drmModeAtomicCommit(), but as I look at the logic it seems that
should be ok. I'm starting to suspect I only see this issue
because I don't have the framebuffer console enabled, so the
kernel has yet to initialize the crtc, and that's probably not
commonly used.
Any thoughts or feedback on a better approach to solving this
issue would be greatly appreciated!
Cc: Marissa Wall <marissaw@xxxxxxxxxx>
Cc: Sean Paul <seanpaul@xxxxxxxxxx>
Cc: Dmitry Shmidt <dimitrysh@xxxxxxxxxx>
Cc: Matt Szczesiak <matt.szczesiak@xxxxxxx>
Cc: Liviu Dudau <Liviu.Dudau@xxxxxxx>
Cc: David Hanna <david.hanna11@xxxxxxxxx>
Cc: Rob Herring <rob.herring@xxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Cc: Robert Foss <robert.foss@xxxxxxxxxxxxx>
Cc: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
drivers/gpu/drm/drm_atomic.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index c2da558..e6404b2 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -2072,6 +2072,9 @@ static int prepare_crtc_signaling(struct drm_device *dev,
for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
s32 __user *fence_ptr;
+ if (!crtc_state->active)
+ continue;
+
fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
--
2.7.4
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