Hello Tejun,
Gentle ping if you missed this email.
Regards,
Akshat
On Mon, Aug 3, 2020 at 9:44 AM Akshat Jain <akshatzen@xxxxxxxxxx> wrote:
>
> Hello Jens Tejun,
> I have a question regarding the ata_gen_passthru_sense function (libata-scsi.c).
>
> This function while generating fixed format sense blocks, puts the
> INFORMATION field at offset 8 and COMMAND-SPECIFIC-INFORMATION at
> offset 16.
> While as per SCSI Primary commands - 4 specification, section 4.5.3
> Fixed format sense data Table 53, the INFORMATION field is at offset 3
> and COMMAND-SPECIFIC-INFORMATION is at offset 8.
>
> Code snippet:
>
> static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
> {
> struct scsi_cmnd *cmd = qc->scsicmd;
> struct ata_taskfile *tf = &qc->result_tf;
> unsigned char *sb = cmd->sense_buffer;
> unsigned char *desc = sb + 8;
> ….
> if ((cmd->sense_buffer[0] & 0x7f) >= 0x72) {
> ....
> } else {
> /* Fixed sense format */
> desc[0] = tf->feature;
> desc[1] = tf->command; /* status */
> desc[2] = tf->device;
> desc[3] = tf->nsect;
> desc[7] = 0;
> if (tf->flags & ATA_TFLAG_LBA48) {
> desc[8] |= 0x80;
> if (tf->hob_nsect)
> desc[8] |= 0x40;
> if (tf->hob_lbal || tf->hob_lbam || tf->hob_lbah)
> desc[8] |= 0x20;
> }
> desc[9] = tf->lbal;
> desc[10] = tf->lbam;
> desc[11] = tf->lbah;
> }
> }
>
> Link to spec: https://www.t10.org/cgi-bin/ac.pl?t=f&f=spc4r37a.pdf
>
> My team has confirmed this observation. Do you believe our
> interpretation of the specification is correct and if yes does this
> need to be corrected?
>
> Regards,
> Akshat Jain
