Isochronous USB transfers on RPI?

[Jakob Alvermark]

Hi,

I see that there is code, I'm not just very good at reading and writing it. :-)

usbdump is quiet on the Pi
On my laptop I can see ISOC packets when using the same webcam and software so something is missing.

/Jakob

On 16 jan 2013, at 13:19, Hans Petter Selasky wrote:

> On Wednesday 16 January 2013 10:25:38 Jakob Alvermark wrote:
>> Hi,
>> 
>> Maybe this should go to the usb list, but it is probably relevant here as
>> well. I have been playing with the Pi for a while now and having great fun
>> with FreeBSD. Great work gonzo and others!
>> However, I'd like to use a webcam with it. I learned that USB webcams use
>> isochronous transfers and the DWC OTG driver doesn't fully implement it.
>> (If I read the commit logs correctly)
>> What is missing and how can I help?
>> 
> 
> Hi,
> 
> The DWC OTG driver has not fully implemented isochronous. Using isochronous 
> transfers will have a high CPU load impact, because 1000 IRQ's (FS) or 8000 
> IRQ's (HS) second will be needed to feed the FIFOs. However, if this is 
> acceptable, code can be found in:
> 
> sys/dev/usb/controller/dwc_otg.c
> 
> --HPS
>