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. An interesting thing is that my system only has one usb port. Here is the output of lspci -v related to the usb controller: 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? Any other idea on how to fix this? José Full output of lspci -v follows. -------------------------------- 00:00.0 Host bridge: VIA Technologies, Inc. VT8501 [Apollo MVP4] (rev 04) Flags: bus master, medium devsel, latency 32 Memory at 20000000 (32-bit, prefetchable) [size=32M] Capabilities: [a0] AGP version 2.0 00:01.0 PCI bridge: VIA Technologies, Inc. VT8501 [Apollo MVP4 AGP] (prog-if 00 [Normal decode]) Flags: bus master, 66MHz, medium devsel, latency 0 Bus: primary=00, secondary=01, subordinate=01, sec-latency=0 I/O behind bridge: 0000a000-0000afff Memory behind bridge: 40000000-470fffff Prefetchable memory behind bridge: 48000000-4f0fffff 00:07.0 ISA bridge: VIA Technologies, Inc. VT82C686 [Apollo Super South] (rev 19) Subsystem: Mitac Unknown device 5133 Flags: bus master, stepping, medium devsel, latency 0 00:07.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06) (prog-if 8a [Master SecP PriP]) Flags: bus master, stepping, medium devsel, latency 64 I/O ports at 1100 [size=16] Capabilities: [c0] Power Management version 2 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 00:07.4 Bridge: VIA Technologies, Inc. VT82C686 [Apollo Super ACPI] (rev 20) Flags: medium devsel, IRQ 9 00:07.5 Multimedia audio controller: VIA Technologies, Inc. VT82C686 AC97 Audio Controller (rev 21) Subsystem: Mitac Unknown device 5133 Flags: medium devsel, IRQ 10 I/O ports at 3100 [size=256] I/O ports at 3200 [size=4] I/O ports at 3204 [size=4] Capabilities: [c0] Power Management version 2 00:07.6 Communication controller: VIA Technologies, Inc. AC'97 Modem Controller (rev 20) Subsystem: Mitac Unknown device 5133 Flags: medium devsel, IRQ 10 I/O ports at 3300 [size=256] Capabilities: [d0] Power Management version 2 00:0a.0 CardBus bridge: Texas Instruments PCI1211 Subsystem: Mitac Unknown device 5133 Flags: bus master, medium devsel, latency 168, IRQ 10 Memory at 14000000 (32-bit, non-prefetchable) [size=4K] Bus: primary=00, secondary=02, subordinate=05, sec-latency=176 Memory window 0: 10000000-11fff000 (prefetchable) Memory window 1: 12000000-13fff000 I/O window 0: 00001800-000018ff I/O window 1: 00001c00-00001cff 16-bit legacy interface ports at 0001 01:00.0 VGA compatible controller: Trident Microsystems CyberBlade/i7d (rev 5d) (prog-if 00 [VGA]) Subsystem: Mitac Unknown device 5133 Flags: bus master, 66MHz, medium devsel, latency 8, IRQ 10 Memory at 40000000 (32-bit, non-prefetchable) [size=8M] Memory at 40800000 (32-bit, non-prefetchable) [size=128K] Memory at 41000000 (32-bit, non-prefetchable) [size=8M] Expansion ROM at 48000000 [disabled] [size=64K] Capabilities: [80] AGP version 1.0 Capabilities: [90] Power Management version 1 ------------------------------------------------------------------------- Take Surveys. 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