Re: [Adeos-main] [PATCH+HACK] optimise root stalling

[Jan Kiszka <jan.kiszka@domain.hid>]

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Philippe Gerum wrote:
> On Thu, 2006-09-28 at 11:15 +0200, Jan Kiszka wrote:
>> Philippe Gerum wrote:
>>> On Mon, 2006-09-25 at 09:35 +0200, Jan Kiszka wrote:
>>>
>>> This one won't work. We need to forcibly re-enable the hw IRQs upon root
>>> unstall requests, regardless of the fact that interrupts are pending in
>>> the log; some code rely on this. E.g. Adeos/ppc over 2.4 would remain
>>> stuck in the delay calibration routine, but there are other more tricky
>>> places where this would bite too.
>> But this would be ok?
>>
>> #else  /* !CONFIG_SMP */
>>         __clear_bit(IPIPE_STALL_FLAG,
>>                     &ipipe_root_domain->cpudata[cpuid].status);
>>
>>        if (unlikely(ipipe_root_domain->cpudata[cpuid].irq_pending_hi !=
>>            0)) {
>>                local_irq_disable_hw();
>>                __ipipe_sync_pipeline(IPIPE_IRQMASK_ANY);
>>        }
>>        local_irq_enable_hw();
>> #endif /* CONFIG_SMP */
>>
>> So we can still save one disable IRQ in the fastpath.
>>
> 
> But in such a case, you would have to use clear_bit() to keep atomicity.

This is for UP, not SMP.

Jan


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