Re: [PATCH v2] ata: libata-sata: Use LBA from sense data descriptor

[Niklas Cassel <cassel@kernel.org>]

On Thu, Apr 10, 2025 at 03:02:33PM +0200, Niklas Cassel wrote:
> 
> I guess now when we do have access to the information, the most consistent
> thing would be to fill all field we can in qc->result_tf... but, to do this
> for every IO might slow things down.
> 
> So is there perhaps some logic to only filling LBA (in addition to STATUS
> and ERROR, which are filled for all NCQ commands), since that is the only
> field that can change, as per the specs.

Looking at this more closely:
https://github.com/torvalds/linux/blob/v6.15-rc1/include/linux/libata.h#L574-L577

FEATURE is a union with ERROR, so we cannot save it in qc->result_tf.

COMMAND is a union with STATUS, so we cannot save it in qc->result_tf.


The sense data descriptor does not provide AUXILIARY, nor DEVICE,
so we cannot save these.


I will send a v3 that does populate COUNT (7:0) and COUNT (15:8),
since it is only so few fields that we do have, we might as well
populate them properly.


Kind regards,
Niklas