Re: TRIM/UNMAP/DISCARD via ATA Passthrough

From: Hannes Reinecke
Date: Fri Sep 16 2016 - 07:16:57 EST

On 09/15/2016 10:52 PM, Jason A. Donenfeld wrote:
> Hi Martin,
> On Thu, Sep 15, 2016 at 6:07 PM, Martin K. Petersen
>> But how do they signal that ATA passthrough is possible? Is there an ATA
>> Information VPD page? Is REPORT SUPPORTED OPERATION CODES supported?
>> We need really solid discovery data before we can entertain enabling
>> something like this.
> `sg_opcodes` said invalid request, so I think there isn't REPORT
> SUPPORTED OPERATION CODES, and `sg_vpd -p ai` came up illegal too.
> However, sg_sat_identify worked reliably, which means a solid way of
> probing this would be to send IDENTIFY DEVICE ATA via SG_ATA_16 or
> SG_ATA_12.
> Let me know and I can give you access to the hardware if you're curious.
Sadly, that's not sufficient.
linux is not the only provider of an SATL (mpt3sas being the most
prominent other one).
And while they might support ATA_12/ATA_16, there is no indication that
you can pass DSM TRIM that way.


Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 NÃrnberg
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