On Mon, 2 Apr 2007, Sebastian Kemper wrote: > Hello, > > I have a Bluetooth dongle from MSI with a Cambridge Silicon Radio, Ltd > chip. I noticed these messages flashing by when I plugged it in: > > Apr 2 16:07:42 section_eight usb 2-3: new full speed USB device using > ohci_hcd and address 5 > Apr 2 16:07:42 section_eight usb 2-3: device descriptor read/64, > error -62 > Apr 2 16:07:42 section_eight usb 2-3: configuration #1 chosen from 1 > choice > Apr 2 16:07:43 section_eight hcid[5733]: Bluetooth HCI daemon > Apr 2 16:07:43 section_eight hcid[5733]: HCI dev 0 up > Apr 2 16:07:43 section_eight hcid[5733]: Starting security manager 0 > Apr 2 16:07:43 section_eight sdpd[5744]: Bluetooth SDP daemon > > The device does work fine, though. Anyway, I tried to narrow the issue > down. It turns out that this seems to be related to CONFIG_HZ. With > CONFIG_HZ=100 I never see the "device descriptor read/64, error -62" > line. With CONFIG_HZ=1000 is get it almost all the time. > > I tried to narrow it down to a change in the code. I thought about > finding a kernel version where this doesn't happen with CONFIG_HZ=1000 > and doing a git bisection. But I took me quite a lot of time and I > didn't find anything useful. I was able to reproduce this with all the > kernels I tested. 2.6.19, 2.6.20 and 2.6.21 up to -rc5. As I already > said it took me a lot of time and I couldn't find a kernel that didn't > have the read errors with CONFIG_HZ=1000. I don't have the time (nor > the nerves) to check every kernel that features CONFIG_HZ=1000.
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 ------------------------------------------------------------------------- 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
