On Wed, 29 Nov 2006, José Alfredo Cañizo Rincón wrote: > On my system, kernel 2.6.18.3 sends repeated messages which keep > > appearing on every console and in the system logs at a rate of four > > per second or so since boot. > > > > On the console: > > > > hub 1-0:1.0: over-current change on port 2 > > > > In system logs: > > > > Nov 28 02:36:58 mundolimite kernel: hub 1-0:1.0: trying to enable port power > on non-switchable hub > > Nov 28 02:36:58 mundolimite kernel: hub 1-0:1.0: state 7 ports 2 chg 0000 evt > 0004 > > Nov 28 02:36:58 mundolimite kernel: uhci_hcd 0000:00:07.2: port 2 portsc > 0980,00 > > Nov 28 02:36:58 mundolimite kernel: hub 1-0:1.0: over-current change on port 2 > > > > The problem disappears by unloading the module uhci_hcd. However, if > > the module remains loaded, the usb port seems to work perfectly, > > though these annoying messages keep appearing and filling the system > > log. The problem does not happen with any of the 2.4 kernels I've > > tried.
That's because the 2.4 driver doesn't report overcurrent conditions. I think. > An interesting thing is that my system only has one usb port. Here is the > > output of lspci -v related to the usb controller: The computer may have only one physical port, but the UHCI controller has two sets of I/O lines. Apparently the unused set has been wired in such a way that the overcurrent input constantly changes state. > 00:07.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 > Controller (rev 0a) (prog-if 00 [UHCI]) > > Subsystem: VIA Technologies, Inc. (Wrong ID) USB Controller > > Flags: medium devsel, IRQ 11 > > I/O ports at 3000 [disabled] [size=32] > > Capabilities: [80] Power Management version 2 > > > > The computer is a Chembook laptop with an AMD-K6-III processor > > (about four years old, manufactured by ChemUSA). The kernel was > > compiled with CONFIG_USB_DEBUG=y. It is > > $ uname -a > > Linux mundolimite 2.6.18.3 #1 Mon Nov 27 22:51:30 CET 2006 i586 GNU/Linux > > > > After looking around it seems that a similar error happens in Compaq > > Armada laptops; see > > https://launchpad.net/distros/ubuntu/+source/linux-source-2.6.15/+bug/8772 > > http://lists.linuxcoding.com/rhl/2004/msg42957.html > > > > Note that the hardware reported by lspci in the first of these pages > > is similar to mine (my complete lspci -v output is below at the end of > > the message). There, it was finally considered to be a hardware > > problem, which might be correct, but on my system usb works well. At > > least there must be a way to stop them from constantly filling the > > system log. Comments in uhci_hcd.c say some features are disabled for > > certain faulty controllers; maybe disabling this over-current warning > > for this particular hardware is worth it? There's nothing to indicate the controller is faulty; more likely the wiring on the motherboard is. Furthermore, that warning message isn't produced by uhci-hcd; it's produced by the hub driver (you'll find it in drivers/usb/core/hub.c). > Any other idea on how to fix this? There are a few possibilities. For example, we could add a sysfs attribute file listing ports which should not be monitored for an overcurrent condition. 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-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel