On Tue, 3 Apr 2007, Sebastian Kemper wrote: > On Monday 02 April 2007 22:20, you wrote: > > It seems pretty obvious that your problem isn't caused by a change in > > the code -- if it were then switching from CONFIG_HZ=1000 to 100 > > wouldn't make any difference. More likely there is some timeout in > > the hub driver which is just a little too short for your device. > > When your clock only has 10-ms resolution instead of 1-ms resolution, > > that could make the difference. > > > > You might try editing drivers/usb/core/hub.c. Increase some of the > > values defined for HUB_ROOT_RESET_TIME, HUB_SHORT_RESET_TIME, and > > HUB_LONG_RESET_TIME. > > > > Alan Stern > > Hello Alan, > > I played with HUB_ROOT_RESET_TIME (default 50 ms) and found that 90 ms > works. I booted three times to make sure. I also booted three times > with 80 ms and I received the same read error every time. > > But the 40 ms apart can't be explained by the 10 ms to 1ms resolution > step that you get when moving from CONFIG_HZ=100 to CONFIG_HZ=1000, can > they? I figure 9ms apart would make sense, but nothing larger or equal > than 10 ms would.
I don't understand it either. The USB spec lists 50 ms as the minimum reset time with no maximum, so increasing it won't hurt. On the other hand, maybe we don't really need to. > Anyway, should I patch HUB_ROOT_RESET_TIME every time I compile a fresh > kernel or is this read error superficial (because the device seems to > work)? As long as the device works, it doesn't matter that the very first reset fails. The driver retries multiple times. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
