Re: [SOLVED ?] VIA KT400 + Kernel 2.6.12 + IO-APIC + ehci_hcd = IRQ trouble

From: Michel Bouissou
Date: Wed Jul 27 2005 - 13:00:27 EST

Le Mardi 26 Juillet 2005 21:44, Michel Bouissou a écrit :
> > Now I'm running with IO-APIC enabled, bus USB 2.0 and ehci completely
> > disabled (both in BIOS and modprobe.conf).
> >
> > The system hasn't hanged again, but I haven't tried to play with on-disk
> > ISO filesystems since...
> I just did the same as 1/ and 2/ again, with USB 2.0 disabled, to make my
> mind. It didn't hang (otherwise I would need to reboot before writing this
> message ;-)

Update: The system hasn't hanged anymore and has shown stable and fast since
I've disabled USB 2.0.

Today I've stressed it quite a lot, played with ISOFS, loopback FS, performed
disk-to-disk backups, burned CDs, used wine and dosemu etc. and it worked
perfectly. None of the things that caused it to hang yesterday when USB 2.0
was enabled caused any problem today.

So now it summarizes as :

- Old BIOS, kernel 2.4.x : System perfectly stable (with IO-APIC and USB 2.0)

- Old BIOS, kernel 2.6.12 : With IO-APIC and USB 2.0, "IRQ 21 - nobody cared"
problems. Disabling either IO-APIC or USB 2.0 causes the problem to

- New BIOS, kernel 2.6.12 : With IO-APIC and USB 2.0, uhci and ehci are now on
the same IRQ. System doesn't complain anymore about USB or IRQ lost, BUT it
may completely *HANG* (is unstable) especially under high activity. Nothing
gets logged or displayed as the system purely and simply hangs.
=> With USB 2.0 completely disabled, the problem seems to disappear and the
system looks stable again.


Michel Bouissou <michel@xxxxxxxxxxxx> OpenPGP ID 0xDDE8AC6E
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