On 4/7/20 4:59 PM, Sowjanya Komatineni wrote:
On 4/7/20 4:38 PM, Sowjanya Komatineni wrote:
On 4/7/20 4:36 PM, Sowjanya Komatineni wrote:
On 4/7/20 4:12 PM, Dmitry Osipenko wrote:
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08.04.2020 01:22, Sowjanya Komatineni пишет:
On 4/7/20 3:08 PM, Dmitry Osipenko wrote:
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08.04.2020 00:08, Sowjanya Komatineni пишет:
...
I think you need a semaphore with resource count = 2.
we hold on to issuing capture if more than 2 buffers are queued
and it
continues only after fifo has min 1 slot empty
Just want to close on this part of feedback. Hope above
explanation is
clear regarding triggering/issuing at max 2 frame capture to VI
HW and
also regarding capture threads where they use
wait_event_interruptible
to prevent blocking waiting for buffers to be available for
captures.
So no changes related to this part are needed in v7.
From what I see in the code, you "hold on" by making kthread to
spin in
a busy-loop while caps_inflight >= SYNCPT_FIFO_DEPTH. So some change
should be needed to prevent this.
The wait_event_interruptible seems should be okay.
We don't want to prevent that as we already have buffers available
for
capture so as soon as VI HW issuing single shot is done and when
min 1
slot is empty we should continue with issuing for another capture.
As long as buffers are available, we should continue to capture and
should not hold
I suppose that taking a shot takes at least few milliseconds, which
should be unacceptable to waste.
As long as buffers are in queue we have to keep processing each
buffer and between buffers obviously we have to wait for previous
frames to finish and this why we have separate thread for frame
finish where we can have next buffer capture ready and issue while
previous frame memory write happens
Also we specified numbers buffers as 3 to vb2 queue. So this is rare
case but to prevent issuing more than 2 at a time as VI HW is only
double buffered and syncpt fifo max depth is 2 added this to be safer.
To be more clear, when more buffers are enqueued from userspace always
capture list will be full and thread will be busy in capture till either
error or stop stream request happens.
