Comment 15 for bug 47768

on one test machine i have the same problem, it seems to be a problem with some chipsets and newer kernel ? -hal? (hoary, breezy and demudi (sarge) had no problems on that machine).
If there is anything connected to any USB port at boot time, i get a freeze at "Mounting root filesystem" (without usplash i can see it hanging in the USB initialisation), if i boot without anything connected to USB the system starts up normally. But if i connect any USB device i get a total machine freeze again (GUI or not).
Disabling "USB Legacy Support" in BIOS helped as workaround for this machine.
Because it may be chipset related this is the output of lspci and others:

rich@Catdog2:~$ lspci
0000:00:00.0 Host bridge: Silicon Integrated Systems [SiS] 746 Host (rev 10)
0000:00:01.0 PCI bridge: Silicon Integrated Systems [SiS] SG86C202
0000:00:02.0 ISA bridge: Silicon Integrated Systems [SiS] SiS963 [MuTIOL Media IO] (rev 25)
0000:00:02.1 SMBus: Silicon Integrated Systems [SiS] SiS961/2 SMBus Controller
0000:00:02.5 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE]
0000:00:02.7 Multimedia audio controller: Silicon Integrated Systems [SiS] Sound Controller (rev a0)
0000:00:03.0 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 0f)
0000:00:03.1 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 0f)
0000:00:03.2 USB Controller: Silicon Integrated Systems [SiS] USB 2.0 Controller
0000:00:09.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host Controller (rev 43)
0000:00:0a.0 Ethernet controller: 3Com Corporation 3c905 100BaseTX [Boomerang]
0000:00:0b.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)
0000:00:0b.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)
0000:01:00.0 VGA compatible controller: STMicroelectronics STG4000 [3D Prophet Kyro Series] (rev 07)
rich@Catdog2:~$ uname -a
Linux Catdog2 2.6.15-25-k7 #1 SMP PREEMPT Wed Jun 14 11:43:20 UTC 2006 i686 GNU/Linux
rich@Catdog2:~$ cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 6
model : 10
model name : AMD Athlon(tm) XP 2800+
stepping : 0
cpu MHz : 2087.826
cache size : 512 KB