Re: [PATCH 1/3] ata: sata_dwc_460ex: use "dmas" DT property to find dma channel

[Julian Margetson]

On 12/19/2015 1:05 PM, Måns Rullgård wrote:
> Andy Shevchenko <andy.shevchenko@xxxxxxxxx> writes:
>
> > On Sat, Dec 19, 2015 at 5:40 PM, Måns Rullgård <mans@xxxxxxxxx> wrote:
> >
> > > OK, I've found something.  The dma setup errors are benign, caused by
> > > the driver calling dmaengine_prep_slave_sg() even for non-dma
> > > operations.
> > I suppose the following is a quick fix to avoid preparing descriptor
> > for non-DMA operations (not tested anyhow)
> >
> > a/drivers/ata/sata_dwc_460ex.c
> > +++ b/drivers/ata/sata_dwc_460ex.c
> > @@ -1041,6 +1041,9 @@ static void sata_dwc_qc_prep_by_tag(struct
> > ata_queued_cmd *qc, u8 tag)
> >                  __func__, ap->port_no, get_dma_dir_descript(qc->dma_dir),
> >                   qc->n_elem);
> >
> > +       if (!is_slave_direction(qc->dma_dir))
> > +               return;
> > +
> >          desc = dma_dwc_xfer_setup(qc);
> >          if (!desc) {
> >                  dev_err(ap->dev, "%s: dma_dwc_xfer_setup returns NULL\n",
> I already have a better patch sitting here.
>
> > > The real error is the lock recursion that's reported
> > > later.  I wasn't seeing it since I was running a UP non-preempt kernel.
> > > With lock debugging enabled, I get the same error.  This patch should
> > > fix it.
> > > -       spin_lock_irqsave(&ap->host->lock, flags);
> > >          hsdevp->cmd_issued[tag] = cmd_issued;
> > > -       spin_unlock_irqrestore(&ap->host->lock, flags);
> > > +
> > This will create a second empty line, though I don't care it is so minor.
> The patch leaves one blank line before the following block comment.  I
> think it looks better that way.

Still can't get the patch applied .

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