Re: [PATCH] libata: Handle SATA bridges better

[Tejun Heo <htejun@gmail.com>]

Alan Cox wrote:
>> I think host side detection should work as long as the bridge properly
>> releases CBLID after IDENTIFY.  Drive side detection seems hopeless
>> unless the bridge modifies IDENTIFY data accordingly.  Maybe the best we
>> can do here is allowing user to select transfer mode.  :-(
> 
> There are far too many systems with this kind of bridge to just dump it
> on the user. I'll have a think about doing it only if the controller
> hasn't decided the cable is 40 wire. That might work.

Okay.

>>>> Another problem is that there are still codes which interpret ap->cbl ==
>>>> ATA_CBL_SATA as SATA host port.  They need to be fixed first before
>>>> using ap->cbl for the actual cable type.
>>> I thought we had those all sorted now. A grep shows there is nobody doing
>>> conditional checking off the ap->cbl cable in drivers/ata any more. They
>>> did in the past - which is this patch got held up - but no longer that I
>>> can see.
>> Hmm... I was looking at sata_scr_valid().  I think this needs to be
>> converted to ATA_FLAG_SATA test too.
> 
> Possibly but PATA controllers don't have ->scr_read so its ok as is.

I'll submit a patch just in case.  I think we used to do depend on that
for PATA/SATA combined controllers before new init model.

Thanks.

-- 
tejun