Re: [RFC] ata/core: don't enable the interrupt while activating the host

[Sergei Shtylyov <sshtylyov@mvista.com>]

Hello.

Sebastian Andrzej Siewior wrote:

>> On 03/26/2010 07:04 AM, Sebastian Andrzej Siewior wrote:
>>     
>>>> Can you please play with ata_sff_freeze() and find out why it's not
>>>> working?
>>>>         
>>> I've been there. I've moved the functions around and nothing changed.
>>> After removing the ATA_NIEN bit it started working. So it looks like
>>> ->sff_check_status() & ->sff_irq_clear() are not clearing the interrupt
>>> for what reason ever.
>>>       
>> What happens if you remove everything else from the function and just
>> set ATA_NIEN?
>>     
>
> removing everything from ata_sff_freeze() makes the interrupt storm go
> away.
> Leaving
> - ap->ctl |= ATA_NIEN;
>   => seems to work
> - the upper and "ap->last_ctl = ap->ctl;"
>   => seems to work
> - the upper and "iowrite8(ap->ctl, ioaddr->ctl_addr);"
>   => irq storm on request irq.
>
> ata_sff_check_status() does not report ATA_DRQ set so I don't know why
> the interrupt is comming.
>   

   Perhaps the drive incorrectly triggers interrupt on setting the nIEN 
bit -- some drives are known to do this; there is a blacklist of such 
drives in the IDE core so that it avoids setting nIEN bit for them.

WBR, Sergei