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Re: uvideo webcam on big-endian systems

Jeremy Morse wrote:

On 20.12.10 16:05:44 you wrote:

> It's possible that the problem is in the ehci driver instead (the isoc
> parts of which have never been tested on a big endian system either).
> Is your webcam attaching at ehci?

Yes. It's an iBook G4.

I also tested on my Pegasos2/G3 running ofppc a few days ago, which has uhci
only. The system reacts with a spontaneous reboot when I try to read from

Both are running 5.99.41.

> If so, could you recompile with EHCI_DEBUG enabled (and "ehcidebug" in
> src/sys/dev/usb/ehci.c set to 5), try to stream again and post the
> resulting messages? Be aware this'll produce a large amount of
> kernel-message spam.

Ok. Here you find the ehci debug log for attaching the webcam:

Streaming is problematic. Similar to the Pegasos my iBook reboots before the
first frame can be shown when EHCI_DEBUG is enabled. All I got before the
reboot is here:

> Additionally, what software are you using to stream video with? Is

I'm using a recent mplayer like this:
$ mplayer tv:// -tv driver=v4l2:device=/dev/video0 -fps 30

> there any indication that any data is being delivered to the
> application (ie, does the green-stripe pattern change at all?).

I would think that from time to time a few pixels are changing, but it is
hardly noticeable.

Here is a photo from the mplayer-window showing the pattern (without

> Right now I'm trying to figure out whether the fault is in configuring
> the device (resulting in no data being sent), or somewhere between data
> being received and the video driver.

I fear that you may be right with ehci's isoc-mode being the culprit.

Frank Wille

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