Re: [linux-usb-devel] Re: [BUG] oops while completing async USB via usbdevio

From: Harald Welte
Date: Tue May 31 2005 - 17:14:01 EST


On Tue, May 31, 2005 at 11:53:24AM -0700, David Brownell wrote:
> I'm still hoping that one of the folk who want make an interesting and
> useful contribution to Linux will take the hint. It goes slowly. :)

I've pondered about three times whether to start or not. I'd rather
not, since I'm already having problems keeping up with all my other
projects :(

> > meanwhile, the current usbfs aio handling is the only way how to deal
> > with delivery of interrupt pipe URB's to userspace drivers.
>
> Other than tying up the file descriptor with a blocking read, that is.

you're probably using that same file descriptor for reading/writing
from/to bulk endpoints at the same time. I don't see how a 'blocking
read' would help.

> > Wouldn't it help to associate the URB with the file (instaed of the
> > task), and then send the signal to any task that still has opened the
> > file? I'm willing to hack up a patch, if this is considered a sane fix.
>
> Sounds reasonable, except that not all such tasks will want the signal.
> Though I guess the infrastructure to filter the signal out already exists,
> so the main missing piece is that urb-to-file binding.

Ok, I'll get something coded shortly.

--
- Harald Welte <laforge@xxxxxxxxxxxx> http://gnumonks.org/
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