Re: 2.6.24-rc8 hangs at mfgpt-timer

From: Willy Tarreau
Date: Mon Jan 21 2008 - 19:00:44 EST


Hi Jordan,

On Mon, Jan 21, 2008 at 04:27:09PM -0700, 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?

Yes of course :

[ 44.013100] NET: Registered protocol family 16
[ 44.066308] geode-mfgpt: IRQ MSR=0:0
[ 44.110161] geode-mfgpt: NMI MSR=0:0
[ 44.154037] geode-mfgpt: Unrestricted sources=0

Then it hangs here.
In another mail I sent privately to Andres, I noticed that it was the
following line which hangs at first iteration (i == 0) :

val = geode_mfgpt_read(i, MFGPT_REG_SETUP);

I have a tinybios 0.98 with no workaround option configurable. I also
have CONFIG_GEODE_MFGPT_TIMER=n.

Hoping this helps,
Willy

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