On 5/30/2025 9:04 AM, Dmitry Baryshkov wrote:
On Fri, 30 May 2025 at 02:15, Jessica Zhang
<jessica.zh...@oss.qualcomm.com> wrote:
From: Abhinav Kumar <quic_abhin...@quicinc.com>
The checks in msm_dp_bridge_atomic_enable() for making sure that we are in
ST_DISPLAY_OFF OR ST_MAINLINK_READY seem redundant.
DRM fwk shall not issue any commits if state is not ST_MAINLINK_READY as
msm_dp's atomic_check callback returns a failure if state is not
ST_MAINLINK_READY.
What if the state changes between atomic_check() and atomic_enable()?
There are no locks, cable unplugging is async, so it's perfectly
possible.
For the ST_DISPLAY_OFF check, its mainly to guard against a scenario that
there is an atomic_enable() without a prior atomic_disable() which once
again should not really happen.
Since it's still possible for the state machine to transition to
ST_DISCONNECT_PENDING between atomic_check() and atomic_commit(), change
this check to return early if hpd_state is ST_DISCONNECT_PENDING.
Can we really, please, drop the state machine? I had other plans for
the next week, but maybe I should just do it, so that by the end of
6.17 cycle we can have a merged, stable and working solution? This
topic has been lingering for months without any actual change.
FWIW, I'm currently working on the state machine rework by the middle of
next week.
I'm anticipating that the rework itself will take some time to get
merged, so didn't want MST to get delayed more by this series.
Thanks,
Jessica Zhang
Signed-off-by: Abhinav Kumar <quic_abhin...@quicinc.com>
Signed-off-by: Jessica Zhang <jessica.zh...@oss.qualcomm.com>
---
drivers/gpu/drm/msm/dp/dp_display.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
b/drivers/gpu/drm/msm/dp/dp_display.c
index 1d7cda62d5fb..f2820f06f5dc 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1512,7 +1512,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge
*drm_bridge,
}
hpd_state = msm_dp_display->hpd_state;
- if (hpd_state != ST_DISPLAY_OFF && hpd_state != ST_MAINLINK_READY) {
+ if (hpd_state == ST_DISCONNECT_PENDING) {
mutex_unlock(&msm_dp_display->event_mutex);
return;
}
--
2.49.0
