I've applied your patch. It seems that results didn't change, but logs differ 2011/11/11 Andiry Xu <andiry.xu@xxxxxxx>: > On 11/08/2011 05:40 AM, Alan Stern wrote: >> On Sat, 5 Nov 2011, Anton Alekseev wrote: >> >>>> Here's the next thing to try: Boot a kernel that was built with >>>> CONFIG_USB_DEBUG enabled, and then mount a debugfs on >>>> /sys/kernel/debug. While running the audio program, go into the >>>> /sys/kernel/debug/usb/ehci/0000:00:12.2 directory and make a copy of >>>> the files there (the only ones that really matter are the "registers" >>>> and "periodic" files). >>>> >>>> Also, get a copy of the /sys/kernel/debug/usb/devices file. Let's see >>>> what all those files have to say. >>> >>> Greetings. >>> Logs in attachments >> >> Unfortunately the information in those files didn't help. It just >> shows that everything was normal while the program was running. >> >> Maybe Andiry Xu will be able to help figure this out. I have no idea >> what's causing the problem, beyond the fact that there's obviously >> something wrong with the EHCI controller. >> > > I checked with HW guys, and they can't think of anything would cause > such long latency. It may take 1~2ms to respond to periodic disable > command, but should not extend to 8ms. > > One thing to try: apply the patch attached, disable PLL quirk and see if > it makes any differences. > > Since it only occur with special initialization parameters, maybe EHCI > is busying on with this special case, but hard to tell what cause the > latency without a PCIE trace. > > Thanks, > Andiry >
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