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.
--
Måns Rullgård
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