RE: 2.6.31.4: WARNING: at arch/x86/kernel/hpet.c:390hpet_next_event+0x70/0x80() [occurs when ACPI_PROCESSOR=y]

[Pallipadi, Venkatesh]

>-----Original Message-----
>From: Justin Piszcz [mailto:jpiszcz@xxxxxxxxxxxxxxx] 
>Sent: Thursday, November 12, 2009 3:57 PM
>To: Thomas Gleixner
>Cc: john stultz; lkml; Pallipadi, Venkatesh; Arjan van de Ven
>Subject: Re: 2.6.31.4: WARNING: at arch/x86/kernel/hpet.c:390 
>hpet_next_event+0x70/0x80() [occurs when ACPI_PROCESSOR=y]
>
>
>
>On Fri, 13 Nov 2009, Thomas Gleixner wrote:
>
>> On Thu, 12 Nov 2009, john stultz wrote:
>>
>>> Forgot to CC lkml, re-adding.
>>
>> Added more CCs
>>
>>> On Thu, 2009-11-12 at 18:25 -0500, Justin Piszcz wrote:
>>>> On Thu, 12 Nov 2009, john stultz wrote:
>>>>> On Thu, Nov 12, 2009 at 8:33 AM, Justin Piszcz 
><jpiszcz@xxxxxxxxxxxxxxx> wrote:
>>>>>> On Thu, 12 Nov 2009, Justin Piszcz wrote:
>>>>>>> On Wed, 11 Nov 2009, Justin Piszcz wrote:
>>>>>>> Again, the problem:
>>>>>>> [    3.318770] cpuidle: using governor ladder
>>>>>>> [    3.321556] ------------[ cut here ]------------
>>>>>>> [    3.321560] WARNING: at arch/x86/kernel/hpet.c:390
>>>>>>> hpet_next_event+0x70/0x80()
>>>>>>> [    3.321561] Hardware name:
>>>>>>> [    3.321562] Modules linked in:
>>>>>>> [    3.321564] Pid: 0, comm: swapper Not tainted 2.6.31.5 #17
>>>>>>> [    3.321565] Call Trace:
>>>>>>> [    3.321567]  [<ffffffff81042f00>] ? hpet_next_event+0x70/0x80
>>>>>>> [    3.321568]  [<ffffffff81042f00>] ? hpet_next_event+0x70/0x80
>>>>>>> [    3.321571]  [<ffffffff81056724>] ? 
>warn_slowpath_common+0x74/0xd0
>>>>>>> [    3.321573]  [<ffffffff81042f00>] ? hpet_next_event+0x70/0x80
>>>>>>> [    3.321576]  [<ffffffff81077696>] ? 
>tick_dev_program_event+0x36/0xb0
>>>>>>> [    3.321578]  [<ffffffff81077079>] ?
>>>>>>> tick_broadcast_oneshot_control+0x119/0x120
>>>>>>> [    3.321579]  [<ffffffff8107683d>] ? tick_notify+0x22d/0x420
>>>>>>> [    3.321581]  [<ffffffff8106fe37>] ? 
>notifier_call_chain+0x37/0x70
>>>>>>> [    3.321583]  [<ffffffff8107612b>] ? 
>clockevents_notify+0x2b/0x90
>>>>>>> [    3.321586]  [<ffffffff81244848>] ? 
>acpi_idle_enter_bm+0x15f/0x2d3
>>>>>>> [    3.321587]  [<ffffffff812446de>] ? 
>acpi_idle_enter_c1+0xf1/0xfc
>>>>>>> [    3.321590]  [<ffffffff812e6d7a>] ? 
>cpuidle_idle_call+0xba/0x120
>>>>>>> [    3.321593]  [<ffffffff8102b832>] ? cpu_idle+0x62/0xc0
>>>>>>> [    3.321596] ---[ end trace cac202f11005305c ]---
>>>>>>> [    3.553852] cpuidle: using governor menu
>>>>>>
>>>>>> Other user with this problem:
>>>>>> http://lkml.org/lkml/2009/10/2/330 - Nobody responded to 
>his report.
>>>>>>
>>>>>> This has been also been reported on other forums with no 
>fix / conclusion on
>>>>>> any type of fix or work-around.
>>>>>
>>>>> Looks like your hpet is busted, or maybe something is 
>resetting the
>>>>> hpet at exactly the wrong time.
>>>>>
>>>>> What does booting with the attached patch do?
>>>>
>>>> Unfortunately I cannot login fast enough to get a full dmesg:
>>>
>>> So if you comment out the printk I added, does it boot?
>>>
>>>> It continually scrolls with this:
>>>>
>>>> [   11.463500] hpet_next_event: hpet_writel failed: 
>0x9c90955 != 0xa0e8b7b
>>>> [   11.463972] hpet_next_event: hpet_writel failed: 
>0xa0e8b7b != 0x9cb9398
>>>> [   11.475121] hpet_next_event: hpet_writel failed: 
>0x9cb9398 != 0xa0e8b71
>>>> [   11.475144] hpet_next_event: hpet_writel failed: 
>0xa0e8b71 != 0x9ce0459
>>>> [   11.486274] hpet_next_event: hpet_writel failed: 
>0x9ce0459 != 0xa0e8b61
>>>> [   11.486343] hpet_next_event: hpet_writel failed: 
>0xa0e8b61 != 0x9d076c0
>>>> [   11.497492] hpet_next_event: hpet_writel failed: 
>0x9d076c0 != 0xa0e8b4c
>>>> [   11.497962] hpet_next_event: hpet_writel failed: 
>0xa0e8b4c != 0x9d30119
>>>> [   11.509111] hpet_next_event: hpet_writel failed: 
>0x9d30119 != 0xa0e8b3c
>>>> [   11.509134] hpet_next_event: hpet_writel failed: 
>0xa0e8b3c != 0x9d571a9
>>>> [   11.520275] hpet_next_event: hpet_writel failed: 
>0x9d571a9 != 0xa0e8b2f
>>>> [   11.520293] hpet_next_event: hpet_writel failed: 
>0xa0e8b2f != 0x9d7e24d
>>>> [   11.531443] hpet_next_event: hpet_writel failed: 
>0x9d7e24d != 0xa0e8b1d
>>>> [   11.531947] hpet_next_event: hpet_writel failed: 
>0xa0e8b1d != 0x9da6e46
>>>> [   11.543095] hpet_next_event: hpet_writel failed: 
>0x9da6e46 != 0xa0e8b0c
>>>
>>> Huh. That's sort of crazy. It almost seems as though you 
>have two offset
>>> HPET timers at one timer location that are switching back and forth.
>>> Looks like either very busted hardware, or something new the kernel
>>> doesn't expect.
>>>
>>>> When I do not load processor.ko though, the error does not occur?

Yes. Yes. This is a hardware errata. I have a patch to workaround this and
waiting on the errata description to get published..

processor.ko part may be a red-herring as we do not use hpet when deep
C-states are not enabled and hence we won't go through this code path.

Thanks,
Venki
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