Re: bttv hang problem on 2.6.8

[Gerd Knorr]

On Mon, Oct 25, 2004 at 05:03:49PM +0200, Lennert Buytenhek wrote:
> (please CC on replies, I'm not on the list)
> 
> Hi,
> 
> When there is a background thread doing VIDIOCSYNC in a loop, issuing
> VIDIOCSPICT in the current thread on the same file descriptor causes
> it to go into uninterruptable sleep and hang.  This is on kernel 2.6.8
> using the bttv driver, and appears easily reproducible.

Don't do that.  bttv serializes ioctls with a lock.  Well, not all of
them, but the ones which change the state of the filehandle, and both
VIDIOCSYNC + VIDIOCSPICT fall into that group.  You simply can't run
them in parallel on the same filehandle.

  Gerd

-- 
#define printk(args...) fprintf(stderr, ## args)
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