[linux-dvb] Non blocking IO on dvr0 device

Felix Domke tmbinc at elitedvb.net
Fri Nov 9 03:33:44 CET 2007


Banana Banana wrote:
> On Nov 9, 2007 12:22 AM, Simon Hargreaves <simon at cellcast.tv> wrote:
>> I'm using
>> 2.6.12-gentoo-r6 #1 SMP kernel.
> Try a more recent kernel?
No, this is not the correct response to a bug.

Or do you remember a bug which was present in that kernel version, and
fixed later? In that case, why don't you point to the diff?

If you want to hunt for the bug, then fine, do a git-bisect or a kernel
diff from your version to the current version, or just try a new
version. But I consider simply throwing in a "please update your
kernel", just because there isn't something better to say, as a bad thing.

Yes, trying a new kernel is certainly a good idea, but I would think the
poster did knew that before. And I would guess he has reasons to stay on
that kernel, be it a customer request, a stable kernel or just the
unwillingness to change something important as the kernel on a
production system.

This was a (perfectly fine) user question, not a developer request. His
question was if there is or was a known bug regarding non-blocking IO on
dvr0. If he wanted to be a kernel developer, he would probably have
posted a patch fixing (or at least explaining) the issue. But he asked
if there is a known issue. Not what he could do to maybe workaround that
problem.

Sorry, just my two cents.

Back to the topic: No, i'm not aware of any leaks occuring using dvr0
recording, and we used that for quite a while on a 2.6.12 machine (until
we finally backported dvb-core for other reasons). Simon, can you
determine the exact moment when memory is lost, and how much it is? Is
it definitely not lost when using blocking IO? Might this be an SMP bug?

Felix



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