From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:41936 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761846Ab3DDP1D (ORCPT ); Thu, 4 Apr 2013 11:27:03 -0400 From: Laurent Pinchart To: Alan Stern Cc: linux-media@vger.kernel.org, linux-usb@vger.kernel.org, Wolfram Sang Subject: Re: [PATCH/RFC] uvcvideo: Disable USB autosuspend for Creative Live! Cam Optia AF Date: Thu, 04 Apr 2013 17:28:01 +0200 Message-ID: <1675297.SBVpg0UeLp@avalon> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Alan, On Thursday 28 March 2013 10:45:27 Alan Stern wrote: > On Thu, 28 Mar 2013, Laurent Pinchart wrote: > > The camera fails to start video streaming after having been autosuspend. > > Add a new quirk to selectively disable autosuspend for devices that > > don't support it. > > > > Signed-off-by: Laurent Pinchart > > --- > > > > drivers/media/usb/uvc/uvc_driver.c | 14 +++++++++++++- > > drivers/media/usb/uvc/uvcvideo.h | 1 + > > 2 files changed, 14 insertions(+), 1 deletion(-) > > > > I've tried to set the reset resume quirk for this device in the USB core > > but the camera still failed to start video streaming after having been > > autosuspended. Regardless of whether the reset resume quirk was set, it > > would respond to control messages but wouldn't send video data. > > Presumably the camera won't work after a system suspend, either. That was my expectation as well, but the device has survived system suspend without being reenumerated. I don't know if the USB port power got cut off during system suspend. > > This solution below is a hack, but I'm not sure what else I can try. Crazy > > ideas are welcome. > > It's not a hack; it's a normal use for a quirk flag. Of course, if you > can figure out what's wrong with the camera and see how to fix it, that > would be best. I've tried to but I can't figure out what goes wrong exactly. > How does the camera perform on a Windows system after being put to > sleep and then woken up? I don't know, I have no Windows system to test the camera on. -- Regards, Laurent Pinchart