Re: SATAPI timing

[Jeff Garzik <jgarzik@pobox.com>]

gp wrote:
> Jeff
> 
> I think I may have found an issue in the ATAPI code in the function 
> atapi_packet_task.
> 
>  From my testing with the sata_via driver, I have been getting a timeout 
> when sending the first inquiry command.
> 
> 
> Here is the section of code of interest:
> 
> 
>     /* make sure DRQ is set */
>     status = ata_chk_status(ap);
>     if ((status & (ATA_BUSY | ATA_DRQ)) != ATA_DRQ)
>         goto err_out;
> 
>     /* send SCSI cdb */
>     DPRINTK("send cdb\n");
>     assert(ap->cdb_len >= 12);
>     ata_data_xfer(ap, qc->cdb, ap->cdb_len, 1);
> 
> ** Wait is needed here to work correctly
> DPRINTK("Wait for a bit\n");
> 
>     /* if we are DMA'ing, irq handler takes over from here */
>     if (qc->tf.protocol == ATA_PROT_ATAPI_DMA)
>         ap->ops->bmdma_start(qc);        /* initiate bmdma */
> 
> 
> In the test case, the dma transfer is being used. From my perusal of the 
> ATA spec in section 9.8, it looks like there needs to be a definite 
> state transition before issuing the bmdma_start.

Yeah, it looks like there needs to be an intrq-wait state in there...

Wanna submit a patch?  :)

	Jeff