Red Hat Bugzilla – Bug 111643
Kernel hangs if IRQ 12 reassigned by BIOS when no PS/2 mouse attached
Last modified: 2007-11-30 17:10:34 EST
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Description of problem:
The stock kernel with Fedora Core 1 (2.4.22-1.2115-nptl) locks up when
attempting to probe a USB bus which has been assigned IRQ 12 by the
BIOS. I do not have a PS/2 mouse attached to my machine, so IRQ 12 is
reassigned by the BIOS to another device (in my case, a USB 2.0
I have found these four workarounds for this problem:
1. Boot installation kernel with "nousb" paramter to void conflict.
Not a very good workaround if you have a USB mouse. :-)
2. Attach a second mouse on the PS/2 mouse port. In this case, both
the PS/2 and USB mice are recognized and work correctly together.
3. Build a custom kernel, disabling PS/2 mouse support. Unfortunately,
there's no way to make PS/2 mouse support a module (!), so it must be
4. In the BIOS setup, mark IRQ 12 as "reserved", preventing the BIOS
from assigning it to anything at all.
Even though #4 is an excellent workaround, this is still a problem
because other operating systems installed on this machine have no
problem at all when the BIOS assigns IRQ 12 to the USB controller.
For a PC hardware novice, this bug is a showstopper right at the start
of Linux installation.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Get a motherboard that reassigns IRQ 12 to the USB controller when
no PS/2 mouse attached. (e.g. Abit KV7)
2. Attach a USB mouse.
3. Do NOT attach a PS/2 mouse.
4. Boot from the Fedore Core 1 installation CD-ROM.
Actual Results: Kernel locks up. Machine must be hard reset.
Expected Results: Kernel should not lock up. Installation screen
Motherboard: Abit KV7, latest BIOS level
Chipset: VIA KT600 / VT8237
Mouse: USB (Microsoft Wireless Optical Mouse Blue)
Output of "lspci":
00:00.0 Host bridge: VIA Technologies, Inc. VT8377 [KT400 AGP] Host
Bridge (rev 80)
00:01.0 PCI bridge: VIA Technologies, Inc. VT8237 PCI Bridge
00:0b.0 FireWire (IEEE 1394): Texas Instruments TSB12LV26 IEEE-1394
00:0c.0 USB Controller: ALi Corporation USB 1.1 Controller (rev 03)
00:0c.3 USB Controller: ALi Corporation USB 2.0 Controller (rev 01)
00:0f.0 RAID bus controller: VIA Technologies, Inc.: Unknown device
3149 (rev 80)
00:0f.1 IDE interface: VIA Technologies, Inc.
VT82C586A/B/VT82C686/A/B/VT8233/A/C/VT8235 PIPC Bus Master IDE (rev 06)
00:10.0 USB Controller: VIA Technologies, Inc. USB (rev 81)
00:10.1 USB Controller: VIA Technologies, Inc. USB (rev 81)
00:10.2 USB Controller: VIA Technologies, Inc. USB (rev 81)
00:10.3 USB Controller: VIA Technologies, Inc. USB (rev 81)
00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
00:11.0 ISA bridge: VIA Technologies, Inc.: Unknown device 3227
00:11.5 Multimedia audio controller: VIA Technologies, Inc.
VT8233/A/8235 AC97 Audio Controller (rev 60)
00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102 [Rhine-II]
01:00.0 VGA compatible controller: nVidia Corporation NV34 [GeForce FX
5200] (rev a1)
Thanks for the bug report. However, Red Hat no longer maintains this version of
the product. Please upgrade to the latest version and open a new bug if the problem
The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases,
and if you believe this bug is interesting to them, please report the problem in
the bug tracker at: http://bugzilla.fedora.us/