Alan Stern wrote: > On Wed, 11 Nov 2009, Stephan Diestelhorst wrote: > > > > This issue is with the built-in Bison web cam in an MSI Wind > > > > U100. Once the camera is enabled (via hotkey), the entire USB > > > > subsystem is not responding anymore, causing non-detection of > > > > freshly attached USB devices and prevents suspending the box. > > > > > > Once again no apologize needed. You should keep cross-posting and > > > report the problem to the linux-usb mailing list. I'm not familiar > > > enough with the EHCI architecture to work on a fix, so the solution > > > will likely come from linux-usb developers. > > > > Any help? > > There's a temporary solution (in one of the threads mentioned above) > described here (the udelay(2000) call): > You should experiment and see if the 2000 can be replaced with a > smaller number. Several volunteers and me have experimented with the udelay values. See https://bugs.launchpad.net/ubuntu/+source/linux/+bug/435352/comments/167 udelay(2000) - works (> 2 people) udelay(1000) - works (knuutsen, catscrash) udelay(600) - works (catcrash) udelay(500) - works (deChrLam with method see # 148, stephan d.) udelay(400)- works (knuutsen, stephan d.) udelay(375) - breaks (stephan d.) udelay(350) - breaks (stephan d.) udelay(300) - breaks (catscrash) udelay(250) - breaks (stephan d.) udelay(100) - breaks (catscrash, stephan d.) udelay(50) - breaks (stephan d., jbob) udelay(48) - breaks (knuutsen) It seems that a delay of 400 usec fixes the thing, and that we're nowhere near the requested 50 usecs. Seems like someone either adds the udelay(400) or introduces a proper fix (with timers). I am too inexperienced in USB things to fully understand the negative implications of the former or do the latter. Many thanks, Stephan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
