Re: [LKP] [x86/platform, acpi] 7486341a98f: genirq: Flags mismatch irq 8. 00000080 (mmc0) vs. 00000000 (rtc0)

[Jiang Liu]

On 2015/3/30 16:28, Li, Aubrey wrote:
> Ying,
> 
> can you please try this patch to see if the problem is gone on your side?
Hi Aubrey,
	I would be better if we could change RTC driver instead.
Thanks!
Gerry
> 
> Thanks,
> -Aubrey
> 
> 
> On 2015/3/26 20:13, Li, Aubrey wrote:
>> On 2015/3/25 15:22, Huang Ying wrote:
>>> [   28.745155] genirq: Flags mismatch irq 8. 00000080 (mmc0) vs. 00000000 (rtc0)
>>
>> okay, I replicated this on my side now.
>>
>> Firstly, I don't think the patch did anything wrong. However, the patch
>> exposes a few issues FWICT currently:
>>
>> - Should we enable RTC Alarm the kind of Fixed hardware event in
>> hardware-reduced ACPI mode? I found RTC required registers in ACPI PM
>> block are not valid(register address = 0)
>>
>> - I checked RTC device in ACPI table, there is no interrupt resource
>> under RTC(firmware bug?), So irq 8 should be a hardcoded number. The
>> question is, shouldn't we update bitmap of allocated_irqs here? Or we
>> assume irq0~15 is reserved? If we assume IRQ0~15 is reserved, then
>> requesting IRQ8 without updating bitmap of allocated_irqs is fine.
>>
>> - Because we don't update bitmap of allocated_irqs when RTC request
>> IRQ8, so when MMC driver allocate irq resource, it's possible it gets
>> irq8, so we saw "genirq: Flags mismatch irq 8. 00000080 (mmc0) vs.
>> 00000000 (rtc0)". So here is another question, when we dynamically
>> allocate irq from irq domain, shouldn't we start from IRQ16? Yes, if
>> allocated_irqs bitmap is updated, then it should be fine if we start
>> from IRQ1.
>>
>> What the patch does is, it changes the behavior of how we allocate irq
>> from irq domain. Previously we have legacy IRQs so we statically assign
>> IRQ numbers for IOAPICs to host legacy IRQs, and now we allocate every
>> IRQ dynamically.
>>
>> For me I think I can deliver a patch against RTC driver to update
>> allocated_irqs bitmap, also, we should free irq when we found RTC ACPI
>> registers are not valid.
>>
>> Certainly I'm open to any suggestions.
>>
>> Thanks,
>> -Aubrey
>>
> 
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