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From: Noboru Iwamatsu <n_iwamatsu@jp.fujitsu.com>
To: Ian.Jackson@eu.citrix.com
Cc: xen-devel@lists.xensource.com
Subject: Re: [PATCH] usbfront: do not assume sequentially mapped pages
Date: Wed, 08 Apr 2009 11:15:20 +0900	[thread overview]
Message-ID: <49DC08B8.3090806@jp.fujitsu.com> (raw)
In-Reply-To: <18907.33293.780084.415818@mariner.uk.xensource.com>

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.

      reply	other threads:[~2009-04-08  2:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-30 15:02 [PATCH] usbfront: do not assume sequentially mapped pages Ian Jackson
2009-04-01  6:05 ` Noboru Iwamatsu
2009-04-01 16:00   ` Ian Jackson
2009-04-06  9:03     ` Noboru Iwamatsu
2009-04-07 16:40       ` Ian Jackson
2009-04-08  2:15         ` Noboru Iwamatsu [this message]

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