On 2002.10.15 19:10 David Brownell wrote:
>> Procedure was following :
>> 1. reboot the computer (software reboot if ok kernel, else reset)
>> 2. go through bios (long initiation with memory testing)
>> 3. when the bootloader shows up (might hang just before, my disks
>> really do not like being stopped before reboot) / when the system
>> hangs, press reset
>> 4. go through bios initialization (bis)
>> 5. when grub shows up, play a bit in the menus (up-down...) then
>> choose a kernel
>>
>> With this protocol I got a 100% boot rate on the original kernel and
>> an almost-always hang with the kernel where debuging was undefed in
>> drivers/usb/host/ohci-hcd.c. It did boot two times (out of maybe
>> 10-15 tries) but that doesn't count since both times the keyboard
>> was dead.
>
> Well, I've seen USB getting annoyingly flakey results in recent
> kernels.
> That's a little bit outside the bounds of the inconsistency I've seen,
> but (I hate to say) not unrealistically so, since you're kicking init
> sequences in different ways. That makes troubleshooting harder!
Well, I knew AMD 756 + USB was a bit risky, guess I was too much in a
2.5 mood when I bought this keyboard.
> There are some one-liners floating around that make it a lot better,
> like making drivers/base/core.c found_match() "return error != 0"
> (true == matched) instead of "return error" (true == failed). That
> one might not be your issue at all, but I've seen it to fix failures
> that closely resemble your "dead devices" mode.
I"ll try this.
>> No such luck. It really looks like ohci is the culprit:(
>
> Maybe not, given that you did report (in an earlier note):
>
> > + ... Unfortunately I've found out today not even CONFIG_USB_DEBUG
> > + was sufficient, since I had a boot hand (cold boot) with my debug
> > + kernel today (warm boot afterwards was ok, though).
>
> Even if it isn't one of the bugs causing generic flakiness, a
> warm-vs-cold boot problem that's ohci-specific isn't something
> that should have appeared in recent kernels. I'd be curious.
> Was 2.5.38 behaving OK for you? Or earlier 2.5 kernels?
I'm afraid I didn't try any 2.5 kernel before 2.5.41.
If you have a particular version you'd like me tot test, I'll do it
(provided it's not one of the disk-eating ones).
I *think* there is a problem in 2.5, and cold booting make it worse,
enabling usb debug makes it better.
*If* I had not both RH8 2.4.18 and w2k booting happily on my hardware
(both cold and warm boots) I would suspect it but that's not the case.
>> P.S.
>>
>> I don't know if it's important, but I had to enable usb keyboard
>> legacy mode in the bios to have keyboard support in the bootloader
>> stage. I had a bad feeling about the option though, a good bios is a
>> lean bios.
>
> Unless your boot loader has a small USB stack, leave that emulation
> enabled in the bios. Linux will disable it when you bring up USB.
>
> But it'd be worth seeing if there were any problems with that. In
> fact,
> in drivers/usb/host/ohci-hcd.c there is one dbg() that could affect
> init timing. Experiment: leave all debug messages off, but change
> the first dbg() call in hc_reset() into an err() call. Does that make
> things better?
I'll do this now, then the found_match thing, and post the results.
Thanks for the suggestions,
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This archive was generated by hypermail 2b29 : Tue Oct 15 2002 - 22:00:56 EST