Hello
I ask because I use 2 Hercules SmartTV for 706x576x25fps YUV420P
grabbing (for MPEG), on a 128MB P4 2.4GHz. I discovered that by default
the bttv driver for Hercules (card=100) allocates not 2 but 5 gbuffers.
If you use RGBA, that makes 706x576x5(gbuffers)x4(bytes/pixel)x4(cards)
or 32MB reserved in the kernel for gbuffers. If you are marginal in
memory, it could cause problems in kernel paging.
Try something like bttv card=100,100,100,100 gbuffers=2 in /etc/modules.
For JPG grabbing, if 40msec jitter is acceptable, it might even be
possible to use only 1 gbuffer.
Here is an uppdate on the oops problem when grabbing from four
Hercules TV cards at the same time.
I tested over the weekend to go back to the original setup
when the capture is done in serial, I tested this with swap and without
swap and it works fine. What I did not mention before was that
X and KDE was running on this computre as well so it seems more and more
like there is a problem with kernel paging when I try to grab from all
four v4l cards at the same time becouse i only have 256MB memeory.
I guess if I use gbuffers=2 when I load the modules and if I
delay the capture with 0.2 or 0.3 between the TV-cards then I guess it
will work I will test that as well now.
If someone is intrested in looking into this then I can post the oopses
again or do more testing if needed.
Johnny
