From: Gregor Jasny <jasny@vidsoft.de>
To: linux-uvc-devel@lists.berlios.de, video4linux-list@redhat.com
Subject: Thread safety of ioctls
Date: Mon, 23 Jun 2008 12:26:10 +0200 [thread overview]
Message-ID: <485F7A42.8020605@vidsoft.de> (raw)
Hi,
in our video conference application the grabbing (QBUF, DQBUF) is done
in a separate thread. The main thread is responsible for the user
interface and queries the controls, input and current standard values
from time to time.
With the latest uvc driver (r217) and vanilla Linux 2.6.25.6 I've
noticed the strange behavior that the grabbing thread hangs in the DQBUF
ioctl. If I remove the control queries from the gui thread everything is
working fine. After the first hang of the driver, even luvcview hangs at
the buffer operation.
With the bttv driver everything works fine. I'll test vivi and pwc
driver later.
My systems are a i686 and one amd64 system with one Logitech 9000 and
one Microsoft NX-6000. I've tried to create a simple testcase, but
suprinsingly this testcase works fine.
Can I enable more logging than setting the trace parameter to 0xfff?
Have you any idea what went wrong here? Is the V4L2-API designed to be
thread safe?
Thanks,
Gregor
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next reply other threads:[~2008-06-23 10:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-23 10:26 Gregor Jasny [this message]
2008-06-23 13:29 ` Thread safety of ioctls Alan Cox
2008-06-23 22:33 ` [Linux-uvc-devel] " Laurent Pinchart
2008-06-24 13:39 ` Alan Cox
2008-06-24 21:34 ` Laurent Pinchart
2008-06-24 22:23 ` Alan Cox
2008-06-24 21:36 ` Mauro Carvalho Chehab
2008-06-24 22:04 ` Laurent Pinchart
2008-06-26 19:48 ` Driver hangs at DQBUF ioctl Gregor Jasny
2008-06-30 15:39 ` [Linux-uvc-devel] " Laurent Pinchart
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