Two frame latency/delay in TX2 V4L stack

Hi Guys,

We use JetPack3.3 & l4t/l4t-r28.2. We found camera capture timestamp (user space with gettimeofday) is two frame later compared with actual camper capture content. We use an time clock gui showing on tx2 board and use camera to capture this clock.

Seems there are about two frames on tx2. We search relative topic below. Do we need to apply relative patch by hand?
How about the latest JetPack3.x? Did it fixed or improved now?

Have a try below patch.


Seems it works. Can you give me more explanation why this patch fix the issue?
Another question is is there any side-effect if we apply this patch?

The patch fix the QUEUED_BUFFERS define as 2, this define hold QUEUED_BUFFERS -1 buffer to return to userspace.
I can’t make sure if any side-effect current still under review/test for this patch.