Re: [GIT PATCHES FOR 2.6.38] Videbuf2 framework, NOON010PC30 sensor driver and s5p-fimc updates

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 13-01-2011 06:46, Andrzej Pietrasiewicz escreveu:
> Hello Mauro,
> 
> On Wednesday, January 12, 2011 9:24 PM Mauro Carvalho Chehab wrote:
>>
>> Em 12-01-2011 08:25, Marek Szyprowski escreveu:
>>> Hello Mauro,
>>>
>>> I've rebased our fimc and saa patches onto
>> http://linuxtv.org/git/mchehab/experimental.git
>>> vb2_test branch.
>>>
>>> The last 2 patches are for SAA7134 driver and are only to show that
>> videobuf2-dma-sg works
>>> correctly.
>>
>> On my first test with saa7134, it hanged. It seems that the code
>> reached a dead lock.
>>
>> On my test environment, I'm using a remote machine, without monitor. My
>> test is using
>> qv4l2 via a remote X server. Using a remote X server is an interesting
>> test, as it will
>> likely loose some frames, increasing the probability of races and dead
>> locks.
>>
> 
> We did a similar test using a remote machine and qv4l2 with X forwarding.
> Both userptr and mmap worked. Read does not work because it is not
> implemented, but there was no freeze anyway, just green screen in qv4l2.
> However, we set "Capture Image Formats" to "YUV - 4:2:2 packed, YUV", "TV
> Standard" to "PAL". I enclose a (lengthy) log for reference - it is a log of
> a short session when modules where loaded, qv4l2 started, userptr mode run
> for a while and then mmap mode run for a while.
> 
> We did it on a 32-bit system. We are going to repeat the test on a 64-bit
> system, it just takes some time to set it up. Perhaps this is the
> difference.

Yeah, I tested where with PAL/M and 64-bits, but I don't think that the hangs
have something due to 64 bits. It is probably because of the high delay introduced
by using the 100 Mbps Ethernet connection to display the stream. This introduces
a high delay (the max frame rate drops from 30 fps to about 6 fps on my setup).
So, qv4l2 will loose frames. This increases the possibility of a race between
qbuf/dqbuf.

Cheers,
Mauro