Mathieu Bérard wrote:
> Tejun Heo a écrit :
>> Rafael J. Wysocki wrote:
>>   
>>> [Adding CCs.]
>>>
>>> On Tuesday, 1 of July 2008, Mathieu Bérard wrote:
>>>     
>>>> Hi,
>>>> I have a laptop with an ICH6M SATA Controller and a Hitachi hard drive.
>>>> While it worked well using the ahci module and Linux 2.6.25, 
>>>> it get randomly 'stuck' for several seconds to several minutes with 2.6.26-rc8.
>>>> Successive errors progressively reduce the ATA link speed.
>>>>
>>>> Passing the libata.noacpi parameter is an effective workaround.
>>>>
>>>> Please note that it's not the first time i have this kind of issue, see:
>>>> http://marc.info/?l=linux-ide&m=117305595312399&w=2
>>>> This was found to be a bad interaction between my _GTF taskfile, which enable the
>>>> "Enable Device-Initiated Interface Power State Transitions" feature, and NCQ.
>>>> The driver was later NCQ blacklisted to correct the problem.
>>>>       
>> Can you please post the result of "hdparm -I /dev/sda" and full kernel
>> boot log?  0xca is not a NCQ command so the it's not related to NCQ at
>> all.  It seems we'll need to filter out DIPM commands from _GTF.
>>
>>   
> Hi,
> hdparm and dmesg output attached.
> 
> I was not expecting anything related to NCQ as my drive is blacklisted,
> I was just mentioning previous issue with that hardware.
> 
> Do you know what has changed in this version that is now causing failure
> with DIPM ?  I could bisect to try to find out, but this will be painful
> as the
> device hang may only appears after several minutes of disk activity.

Can you please test the attached patch?

-- 
tejun