In trying to use drm_hwcomposer with HiKey/HiKey960 boards, I found that the crtc wouldn't intitalize and the atomic commit calls were failing.
I initially chased this down to following check in the kernel drm_atomic_crtc_check() function 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; }
Where because a fence was submitted state->event was set, but the crtc state was not active. This results in the atomic commit to fail and no mode to be set.
After hacking around this in the kernel, Sean Paul helped me understand that it was the kernel complaining about the crtc state being provided in the atomic commit which did not have the active flag set.
Thus, the proper fix is to make sure when we do the modesetting that we also set the crtc state active flag in property set.
With this change, the kernel no longer rejects the atomic commit and the crtc initializes properly.
Cc: Marissa Wall marissaw@google.com Cc: Sean Paul seanpaul@google.com Cc: Dmitry Shmidt dimitrysh@google.com Cc: Robert Foss robert.foss@collabora.com Cc: Matt Szczesiak matt.szczesiak@arm.com Cc: Liviu Dudau Liviu.Dudau@arm.com Cc: David Hanna david.hanna11@gmail.com Cc: Rob Herring rob.herring@linaro.org Signed-off-by: John Stultz john.stultz@linaro.org --- drmdisplaycompositor.cpp | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drmdisplaycompositor.cpp b/drmdisplaycompositor.cpp index acd13b8..3a20b31 100644 --- a/drmdisplaycompositor.cpp +++ b/drmdisplaycompositor.cpp @@ -520,6 +520,13 @@ int DrmDisplayCompositor::CommitFrame(DrmDisplayComposition *display_comp, }
if (mode_.needs_modeset) { + ret = drmModeAtomicAddProperty(pset, crtc->id(), crtc->active_property().id(), 1); + if (ret < 0) { + ALOGE("Failed to add crtc active to pset\n"); + drmModeAtomicFree(pset); + return ret; + } + ret = drmModeAtomicAddProperty(pset, crtc->id(), crtc->mode_property().id(), mode_.blob_id) < 0 || drmModeAtomicAddProperty(pset, connector->id(),