On Mon, 25 Dec 2006 [EMAIL PROTECTED] wrote: > I just upgraded an Inspiron 7500 laptop from RedHat 9 to > Centos 4.3 and the external USB sound no longer works. It worked > fine under RedHat 9. Now my toddlers cannot watch their DVDs > so please help me :-). > > The 2.6.9 CentOS 4.3 kernel starts up usb and goes into a loop > adding and removing the external audio box: ...
> The speakers just click every few seconds and the device gets added and > removed > by the kernel. > > Doing some research, I found mention of problems with overcurrent detection > for some hardware, and I am definitely getting a message to that effect, > so I upgraded the kernel to the latest -- 2.6.20-rc2 -- to > see if the (new) ignore_oc flag would fix this. It changed the behavior but > didn't fix the problem. Looking at the light on the USB audio box it looks > like > it is just enabling and disabling the peripheral at much higher speed. Here > is the appropriate part of the syslog: > Dec 25 12:09:40 laptop kernel: usb 1-1: new full speed USB device using > uhci_hcd and address 2 > Dec 25 12:09:40 laptop kernel: usb 1-1: configuration #1 chosen from 1 choice > Dec 25 12:09:40 laptop kernel: hub 1-0:1.0: port 1 disabled by hub (EMI?), > re-enabling... > Dec 25 12:09:40 laptop kernel: usb 1-1: USB disconnect, address 2 > Dec 25 12:09:40 laptop kernel: usb 1-1: new full speed USB device using > uhci_hcd and address 3 > Dec 25 12:09:41 laptop kernel: usb 1-1: configuration #1 chosen from 1 choice > Dec 25 12:09:55 laptop kernel: usbcore: registered new interface driver > snd-usb-audio > Dec 25 12:09:56 laptop kernel: usb 1-1: USB disconnect, address 3 > The overcurrent fix is working as designed I assume, but there is now the > problem > with the port being "disabled by the hub". The "ignore_oc" option is intended for situations where the hardware generates bogus "overcurrent change" indications; it causes the driver to ignore the indications. But when the indications _aren't_ bogus -- as in your case -- the option won't do any good, as you found out. This is a hardware problem. It can't be fixed by software changes. Either your sound device or your computer's USB controller isn't working right. 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
