Re: ata_std_qc_defer not good enough for FIS-based switching ?

[Tejun Heo <htejun@gmail.com>]

Mark Lord wrote:
> Tejun Heo wrote:
>> Mark Lord wrote:
>>> Mmm.. I just plugged the same PM + drives into my sata_sil24 card here,
>>> and that driver went bonkers when I did the same test.
>>>
>>> Had to reboot eventually to recover.
>>
>> Hmm... That can't be.  Above all, although we do manual scheduling 
>> around sil24, the controller does its own scheduling and will happily 
>> issue command in the right order even if the software scheduler screws 
>> up.  Do you have the log?
> ..
> 
> Here's what was in /var/log/messages after I held the power button
> for five seconds to force a poweroff and then rebooted.  I didn't make much
> effort to learn more, as I'm already busy enough testing/debugging sata_mv.

Hmmm... Have been testing NCQ + non-NCQ heavy load test w/ deadline 
scheduler for 30+ mins now and there's no problem at all.  I'm pretty 
sure sata_sil24 can handle mixed (across different drives) NCQ + non-NCQ 
workload okay.

One catch w/ sata_sil24 is that it has something called PMP DMA CS 
errata which means that all context is lost if any error (including a 
device one) occurs during commands are pending to more than two devices 
behind a port, the controller's state gets completely corrupt, so when 
something goes wrong while lots of commands are pending via PMP, it's 
often impossible what exactly went wrong.

sil4726/3726 also has a quirk.  It has configuration device as the last 
device and issuing random IOs it might cause unpredictable results.  So, 
can you please re-try the test excluding the pseudo config device?

Thanks.

-- 
tejun