On Thursday 17 March 2005 5:27 pm, Antti Andreimann wrote: > > What is the status of this stuff now? Has anyone done any work on this > and what exactly is the problem with current code?
It's in the kernel, and nobody's actually reported trying to _use_ the IN transactions. The passed some testing I did some time back, but until there are real-world success reports I expect problems. So it's marked "experimental". For OUT transactions (e.g. to speakers) the code seems to work when the transaction fits in a single microframe: no splits. There's an issue though with _some_ configurations where the packets are bigger than 188 bytes (two or more microframes); "buzzing sound". I posted some experimental patches Monday last week (?) which don't seem to have helped. I'm not quite sure what's up, and it doesn't happen for me any more. I suspect the microframe scheduling, which is a complicated problem blessed with un-pretty code. If there are issues with IN transactions (e.g. recording microphone inputs), that'd make me suspect the microframe scheduling even more. All IN transactions involve multiple frames. > I did try to turn it on for my USB soundcard (so it would work through a > USB 2.0 hub) and experienced a NULL pointer dereference plus some > spinlock errors. I haven't tried it without pre-emption yet. I am > willing to spend some time to tweak and test it if I'd know what exactly > needs tweaking ;) Those are all new errors. Send stack traces and I can offer suggestions; they'd be the best indicators that anything's wrong! - Dave ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
