Re: [PATCH 1/1] libata-dev: add flush task to ata_exec_internal()

[Tejun Heo <htejun@gmail.com>]

Jeff Garzik wrote:
> Tejun Heo wrote:
> 
>> Yes, we certainly need this. The irq handling isn't really correct 
>> either as irq handlers don't clear interrupt conditions on spurious 
>> interrupts. I hope/plan to address this during EH work.
> 
> 
> Except for the HSM, there is no guaranteed way to know if an interrupt 
> is spurious or not on many controllers, who lack an "I have an 
> interrupt" bit.
> 

What I'm thinking is to disable interrupt (hopefully using controller 
flag, maybe PCI IRQ disable, ATA_NIEN if nothing else is possible) on 
error condition which may breach HSM and force controller and device to 
a known state in ->error_handler() or ->post_internal_command() before 
reenabling interrupt. This method will also make libata resistant to 
screaming IRQ cases some controllers/drives show under certain 
circumstances.

And I think clearing ->hsm_task_state belongs to (to-be-added) 
->post_internal_command() as it belongs to ->eng_timeout but not to EH 
framework.

Thanks.

-- 
tejun