[PATCH v3 2/2] ata: Fix the dma state machine lockup for the IDENTIFY DEVICE PIO mode command.

[Tejun Heo]

On Thu, Jun 19, 2014 at 07:44:28PM +0530, Suman Tripathi wrote:
> Hi Tejun,
> 
> On Thu, Jun 19, 2014 at 12:20:54PM +0530, Suman Tripathi wrote:
> > +     /*
> > +      * Restart the dma engine if the last cmd issued
> > +      * is IDENTIFY DEVICE command
> > +      */
> > +     if (unlikely(ctx->last_cmd[ap->port_no] == ATA_CMD_ID_ATA))
> > +             ahci_restart_engine(ap);
> 
> Is it really only for IDENTIFY?  Are other PIO commands okay?
> [Suman] : We root cause it , It is the IDENTIFY DEVICE command . Other are
> ok
> Theprevious version applied it to all PIO commands, right?
> [suman] : The v2 contains only the IDENTIFY DEVICE. The v1 is contains for
> all PIO commands and that didn't work because the ERRATA mentions that it
> happens for the IDENTIFY DEVICE command.

So, it's just ATA_CMD_ID_ATA and ATA_CMD_ID_ATAPI is okay?  That's
kinda weird.

-- 
tejun