linux-kernel - Re: uvcvideo causes ehci

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.44L0.0910212131560.24481-100000@netrider.rowland.org>
Date:	Wed, 21 Oct 2009 21:36:43 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Laurent Pinchart <laurent.pinchart@...asonboard.com>
cc:	Ozan Çağlayan <ozan@...dus.org.tr>,
	<linux-media@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	USB list <linux-usb@...r.kernel.org>
Subject: Re: uvcvideo causes ehci_hcd to halt

On Thu, 22 Oct 2009, Laurent Pinchart wrote:

> On Wednesday 21 October 2009 22:09:46 Ozan ÃaÄlayan wrote:
> > Laurent Pinchart wrote:
> > > Probably because hal opens the device to query its capabilities and
> > > closes it right after. The driver submits the interrupt URB when the
> > > first user opens the device and cancels it when the last user closes the
> > > device.
> > 
> > So who's guilty now?
> > 
> > :)
> 
> Not me :-)
> 
> I don't think there's anything wrong with submitting an interrupt URB and 
> canceling it soon after.

Nothing wrong at all.  Even if hal didn't do this, the same thing might
very well occur the second time somebody ran a program accessing the
video device.

The real problem will be to figure out why the hardware isn't turning
off the periodic schedule.  It might be a timing issue (the schedule
was running too briefly before the driver tried to disable it).  That
could explain why it shows up only occasionally.  But if it isn't, I
have no idea what the underlying cause is or how to fix it.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/