Re: [BUG] IO-APIC + timer doesn't work!

[Jeff Mahoney <jeffm@suse.com>]

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Jan Kiszka wrote:
> Jeff Mahoney wrote:
>> Hi all -
>>
>> I saw this while booting 2.6.30-rc1, -rc2, and today's git, on one of
>> my development nodes. This output is with apic=debug. With noapic,
>> it still hung. Both outputs follow.
>>
>> git bisect leads to commit 8d6f0c8214928f7c5083dd54ecb69c5d615b516e,
>> but I'm not seeing anything obvious there. Backing just that change
>> out doesn't fix it.

[snip]

> Hmmmmm. That somehow reminds me of what I thought I had to fix in the
> HPET emulation of QEMU just recently [1] - because of 2.6.30-rc's behavior.
> 
> Could you try if writing 'delta' a second time makes any difference on
> that box?
> 
> diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
> index 648b3a2..523d72b 100644
> --- a/arch/x86/kernel/hpet.c
> +++ b/arch/x86/kernel/hpet.c
> @@ -324,6 +324,7 @@ static void hpet_set_mode(enum clock_event_mode mode,
>  		       HPET_TN_SETVAL | HPET_TN_32BIT;
>  		hpet_writel(cfg, HPET_Tn_CFG(timer));
>  		hpet_writel((unsigned long) delta, HPET_Tn_CMP(timer));
> +		hpet_writel((unsigned long) delta, HPET_Tn_CMP(timer));
>  		hpet_start_counter();
>  		hpet_print_config();
>  		break;
> 

Thanks, Jan.

That fixed it for me.

- -Jeff

- --
Jeff Mahoney
SUSE Labs
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