On Friday 27 July 2007, Alan Stern wrote: > > stressing a flash disk I rapidly get this error: > > > Jul 27 12:35:00 oenone kernel: ehci_hcd 0000:00:02.2: devpath 3.4 ep1in > > 3strikes > > Jul 27 12:35:00 oenone kernel: usb-storage: Status code -71; transferred > > 8192/122880 > > > Is there a way I can enable more debugging about this cause of -EPROTO?
dbg_qh() and friends ... but it probably won't say anything much. If it's that reproducible, I suggest you get some kind of USB analyser and throw it at the problem. Notice how it happened rather promptly at the start of a new page; and likely at the start of a new qTD. > In my experience this sort of thing tends to be caused by low-level > hardware communications errors. Noise in the USB data lines or a > missing handshake packet, stuff like that. Not much extra debugging > can be done; the "3strikes" indication comes directly from the > controller hardware. Well, that's one theory. Thing is, this kind of problem happens more often than it should. No matter what causes it, it'd be better to recover from it ... or prevent it from happening. My theory has been different: that some USB peripherals get deeply confused if Linux talks to them "too fast" (i.e. probably anything faster than MS-Windows). Notice how the "recovery" that followed involved a device reset. But -- never actually having had both a highspeed USB sniffer *AND* hardware exhibiting this problem in the same place -- I've not been able to test that theory. - Dave ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
