On 3/28/2024 6:46 PM, Bjorn Andersson wrote:
On Thu, Mar 28, 2024 at 02:21:14PM -0700, Abhinav Kumar wrote:
On 3/28/2024 1:58 PM, Stephen Boyd wrote:
Quoting Abhinav Kumar (2024-03-28 13:24:34)
+ Johan and Bjorn for FYI
On 3/28/2024 1:04 PM, Kuogee Hsieh wrote:
For internal HPD case, hpd_event_thread is created to handle HPD
interrupts generated by HPD block of DP controller. It converts
HPD interrupts into events and executed them under hpd_event_thread
context. For external HPD case, HPD events is delivered by way of
dp_bridge_hpd_notify() under thread context. Since they are executed
under thread context already, there is no reason to hand over those
events to hpd_event_thread. Hence dp_hpd_plug_handle() and
dp_hpd_unplug_hanlde() are called directly at dp_bridge_hpd_notify().
Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_display.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
Fixes: 542b37efc20e ("drm/msm/dp: Implement hpd_notify()")
Is this a bug fix or an optimization? The commit text doesn't tell me.
I would say both.
optimization as it avoids the need to go through the hpd_event thread
processing.
bug fix because once you go through the hpd event thread processing it
exposes and often breaks the already fragile hpd handling state machine
which can be avoided in this case.
It removes the main users of the thread, but there's still code paths
which will post events on the thread.
I think I like the direction this is taking, but does it really fix the
whole problem, or just patch one case?
So kuogee's idea behind this that NON-hpd_isr events need not go through
event thread at all.
We did not run into any special scenario or issue without this. It was a
code walkthrough fix.
PS. Please read go/upstream and switch to b4, to avoid some practical
issues with the way you posted this patch.
Thanks,
Bjorn
Just to elaborate the practical issues so that developers know what you
encountered:
-> no need of v1 on the PATCH
-> somehow this patch was linked "in-reply-to" another patch
https://lore.kernel.org/all/1711656246-3483-2-git-send-email-quic_khsieh@xxxxxxxxxxx/
. This is quite strange and not sure how it happened. But will double
check if we did something wrong here.
Thanks for sharing these.
Looks right to me,
Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
