Re: [BUG] libahci returns stale result tf much of the time.

[Mark Lord <kernel@teksavvy.com>]

On 10-10-04 05:18 AM, Tejun Heo wrote:
> Hello,
>
> On 09/25/2010 01:26 AM, Robert Hancock wrote:
>>> And here's an example of the bug, which should work (as a demo)
>>> for most folks out there with the same controller ahci / JMB360:
>>>
>>> Here, I'll use hdparm to do a "set acoustic" command
>>> on a drive which does NOT have the "Acoustic Management" feature set.
>>> Just look for the fd fd fd strings in the returned data,
>>> and notice how the final IDENTIFY at the end works, but returns
>>> bad ATA status 0x51 from the stale result_tf:
>>
>> The d2h_fis area is supposed to be updated by the controller with
>> the last FIS received from the device. Maybe this controller just
>> isn't doing that for some reason?
>
> Hmm... one possibility is that the controller takes some time to
> update the area and the driver is reading it off too early.  Maybe
> adding a delay would resolve the issue?  Mark, do you know whether
> this problem is isolated to JMB360?
..

That's my theory, too (slow updating of the area).
I haven't pursued it further yet, but I will.

This is really disruptive for me here, as my primary eSATA
adaptor in my notebook is JMB360, and it gets used a LOT.

Cheers