Re: sata_mv & pmp support

[Mark Lord <liml@rtr.ca>]

Mark Lord wrote:
> Tejun Heo wrote:
>> Mark Lord wrote:
> ..
>>> I've just noticed that, if I unplug/replug the host-side SATA cable
>>> on the Sil3726 PM, and *then* "insmod sata_mv", the PM is not found.
>>>
>>> If I then simply do "rmmod sata_mv ; insmod sata_mv", then the PM is 
>>> found.
>>>
>>> This happens with the original hardreset code from Jeff,
>>> as well as the updated sata_mv code that I've posted earlier.
>>> So it is not anything I've broken (recently :) ).
>>>
>>> Very strange.. I wonder if it also happens with the Marvell PM,
>>> except I don't have one here to test with at the moment.
>>>
>>> Ever heard of anything strange like that?
>>
>> IIRC, ICH8 ahci + 4726 fails the initial reset sequence because the 
>> PMP comes up after the hardreset code times out, which triggers 
>> another EH iteration which works out fine.  If the problem is caused 
>> by the PMP not responding fast enough, it should cause a hotplug event 
>> afterwards. 
> ..
> 
> So I ought to be able to insert (for debug purposes only) a msleep(3000)
> at an appropriate location in the code, and suddenly see this problem go 
> away?
> 
> Not for upstream -- the eventual hotplug support in sata_mv is the real solution.
> But just to confirm that this is indeed the issue.
..

Heh.. darned near exactly 3 seconds does it, alright.

Okay, I won't fuss over this for now -- it works if the PM is plugged in
at boot (because the BIOS fiddles it first), and it works when warmplugged
so long as sata_mv is unloaded and reloaded.

This will get fixed completely with the hotplug support fixes coming later this week.

Cheers