Re: 2.6.24-rc8 hangs at mfgpt-timer

From: Arnd Hannemann
Date: Tue Jan 22 2008 - 04:02:56 EST


Jordan Crouse wrote:
> Okay - I've been exploring a little bit more. I talked to the TinyBIOS
> developer, and he verified that TinyBIOS shouldn't use any MFGPT timers.
> He also told me that the mysterious "MFGPT workaround" was in fact the
> magic MFGPT erasing MSR that was in the old kernel driver.
>
> So with the "MFGPT workaround" turned off, TinyBIOS should be acting like
> the OLPC firmware with regards to timers, yet it is not. So that is
> curious. I think I might have identified a race condition in the code,
> but I'm not 100% sure thats the same problem that the ALIX platform is
> seeing.
>
> Anrd and others - will you please try the attached patch on your platform
> with the "MFGPT workaround" turned off and mfgpts enabled, and send out
> the dmesg?

Of course, tinyBios version v0.99, "MFGPT workaround" turned off,
CONFIG_GEODE_MFGPT_TIMER=n:

[ 67.369697] NET: Registered protocol family 16
[ 67.383059] geode-mfgpt: IRQ MSR=0:0
[ 67.394058] geode-mfgpt: NMI MSR=0:0
[ 67.405049] geode-mfgpt: Unrestricted sources=0
[ 67.418909] geode: 8 MFGPT timers available.
[ 67.433211] PCI: PCI BIOS revision 2.10 entry at 0xfcd03, last bus=0

same with CONFIG_GEODE_MFGPT_TIMER=y (sorry, without move printk patch):

[ 22.289349] NET: Registered protocol family 16
[ 22.302716] geode-mfgpt: IRQ MSR=0:0
[ 22.313716] geode-mfgpt: NMI MSR=0:0
[ 22.324704] geode-mfgpt: Unrestricted sources=0
[ 22.338566] geode-mfgpt: Registered timer 0
[ 22.351393] mfgpt-timer: registering the MFGT timer as a clock event.
^^^^ Hangs here

>
> This will give us some debug information that I can use to ensure that
> the interrupts are set up correctly. You can leave the timer tick disabled
> if you want.

>
> Thanks,
> Jordan
>

Arnd
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