Date: Wed, 16 Jan 2013 15:29:23 +0100 From: Jakob Alvermark <jakob@alvermark.net> To: Hans Petter Selasky <hselasky@c2i.net> Cc: freebsd-arm@freebsd.org Subject: Re: Isochronous USB transfers on RPI? Message-ID: <78AB4FEC-6E16-4FCA-B172-3C7B37FEA4DF@alvermark.net> In-Reply-To: <201301161319.17236.hselasky@c2i.net> References: <6BD0E5E4-3921-4F9B-9381-3813933670AE@alvermark.net> <201301161319.17236.hselasky@c2i.net>
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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, >>=20 >> 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? >>=20 >=20 > Hi, >=20 > The DWC OTG driver has not fully implemented isochronous. Using = isochronous=20 > transfers will have a high CPU load impact, because 1000 IRQ's (FS) or = 8000=20 > IRQ's (HS) second will be needed to feed the FIFOs. However, if this = is=20 > acceptable, code can be found in: >=20 > sys/dev/usb/controller/dwc_otg.c >=20 > --HPS >=20
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