Re: [PATCH 1/4] libata: Allow NCQ TRIM to be enabled or disabled with a module parameter

[Hannes Reinecke <hare@suse.de>]

On 05/05/2015 03:31 PM, Tejun Heo wrote:
> On Mon, May 04, 2015 at 09:54:18PM -0400, Martin K. Petersen wrote:
>> We have started seeing SSD firmware updates introduce support for queued
>> TRIM. Sadly, in most cases this support is completely untested and can
>> lead to either errors or data corruption.
>>
>> Add two libata force flags that can be used to either enable or disable
>> queued TRIM support.
>>
>> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
> 
> Applied 1-4 to libata/for-4.2.
> 
> Thanks.
> 
As a side note: queue TRIM requires 'SEND FPDMA QUEUED', which is an
_optional_ part of the NCQ feature set.
And unfortunately there are no identify bits telling us whether SEND
FPDMA QUEUE is actually implemented (or RECEIVE FPDMA QUEUED, for
that matter).
I've been advocating to implement this (it would come in very handy
for the SMR/ZAC stuff) but to no avail so far.
Needless to say, none of the drives I have implement SEND FPDMA
QUEUED...

Maybe it's an idea to poke the powers that be about additional
identify bits for this ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
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