Re: [git patches] libata updates for 2.6.34

[Jeff Garzik <jeff@garzik.org>]

On 03/15/2010 03:33 AM, Zeno Davatz wrote:
> On Mon, Mar 15, 2010 at 3:55 AM, Jeff Garzik<jeff@garzik.org>  wrote:
>> On 03/09/2010 11:26 PM, Tejun Heo wrote:
>>>
>>> Hello, Linus, Jeff.
>>>
>>> On 03/10/2010 07:12 AM, Jeff Garzik wrote:
>>>>
>>>> Coincedentally, it looks like someone else just reported the same
>>>> problem, with 2.6.34-rc1.
>>>>
>>>> It definitely sounds like a race.  READ DMA is a DMA command as the name
>>>> implies, so that eliminates the possibility of polling-related paths in
>>>> ata_sff_interrupt (libata-sff.c).
>>>>
>>>> I'll flip some of my machines to the icky slow boring piix mode, rather
>>>> than sexy AHCI mode :) to see if I can reproduce.  I have had a feeling
>>>> that we needed a more sophisticated IRQ handling setup, this may be what
>>>> was needed.  Lost interrupt recovery should occur faster than 30 seconds
>>>> in any case, and should not require a hard reset if the hardware
>>>> functions just fine outside of the lost-interrupt / race that just
>>>> occurred.
>>>
>>> Yeap, there is a race condition with clearing which I don't think we
>>> can solve completely but with some modification I think we can at
>>> least cover known failure cases.
>>>
>>> For longer term, I don't think we can solve this by diddling with the
>>> SFF registers.  The interface is just way too ancient and horrid to
>>> build anything reliable on top of.  I'm planning on implementing
>>> smarter IRQ storm handling and stepped timeouts for ATA commands.
>>
>> A tester on this bug
>>         http://bugzilla.kernel.org/show_bug.cgi?id=15537
>> seemed to find success with the patch.
>
> Thanks for the Update!
>
> I will wait some more and then test rc-2.

Can you test the patch, please?

	Jeff