Re: SATA port multiplier(Marvell 6121 with ahci) and Marvell 4140, simg 3726

[Tejun Heo <tj@kernel.org>]

Mark Lord wrote:
>>> Dmesg: hotplug-in 3726 into 6145 , and the unplug, finally plug again
>>> ata9: exception Emask 0x10 SAct 0x0 SErr 0x0 action 0xe frozen
>>> ata9: irq_stat 0x02400000, PHY RDY changed
>>> ata9: hard resetting link
>>> ata9: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
>>> ata9.15: qc timeout (cmd 0xe4)
>>> ata9.15: failed to read PMP GSCR[0] (Emask=0x4)
>>
>> Heh.. failing PMP READs.  Doesn't look like there's anything else to do
>> than disabling it.  Will post a patch.
> ..
> 
> No kernel timestamps there, but I do wonder if somehow
> the driver is polling too soon for the PMP?
> I wonder if a short delay in there, before issuing the PMP read,
> might help (or not)?

The timeout is currently 3 secs and the timeout is mostly dependent on
the PMP device and 3726 fares off fine with < 1sec timeouts, so I don't
think it's because of short timeout.

Thanks.

-- 
tejun