From mboxrd@z Thu Jan 1 00:00:00 1970 From: Noboru Iwamatsu Subject: Re: [PATCH] usbfront: do not assume sequentially mapped pages Date: Wed, 08 Apr 2009 11:15:20 +0900 Message-ID: <49DC08B8.3090806@jp.fujitsu.com> References: <18896.57087.861363.142669@mariner.uk.xensource.com> <49D30430.7030700@jp.fujitsu.com> <18899.36772.20935.961285@mariner.uk.xensource.com> <49D9C56B.8060309@jp.fujitsu.com> <18907.33293.780084.415818@mariner.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <18907.33293.780084.415818@mariner.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ian.Jackson@eu.citrix.com Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Ian, I tried out uvccapture-0.5, and I'm certain that we have the same problem. When uvccapture had started memcpy-ing from the v4l2_buffer, the v4l2_buffer was not filled yet. (in line 294 of v4l2uvc.c, vd->buf.bytesused is less than HEADERFRAME1) I'm uncertain whether this problem results from the isoc-transfer timing or v4l relating. Regards, Noboru Ian Jackson wrote: > Noboru Iwamatsu writes ("Re: [Xen-devel] [PATCH] usbfront: do not assume sequentially mapped pages"): >> Ian, >> > You might like to try a v4l uvc driver and see if it works for you. >> >> Sorry for the late reply. >> >> I've been trying USB2.0 UVC webcam too, but I have not succeeded yet. >> I dumped urbs and saw no errors in isoc-urbs. > > I didn't see errors. I ran uvccapture (as in Debian lenny), which > seems to be the most simple test program available, and it segfaults > while accessing what is supposed to be a buffer full of video data > provided by mmapping the kernel's UVC driver. > > Ian.