Re: [PATCH 03/03] omap hsmmc: adaptation of sdma descriptor autoloading feature

Tony Lindgren
2010-03-11T18:39:44Z

* Venkatraman S <svenkatr@ti.com> [100311 07:04]:
> Tony Lindgren wrote:
> >
> > Does the driver still work in PIO mode?
> >
> > We need to have the drivers capable to fail over to PIO mode
> > as the DMA channels can run out.
> >
>
> The driver doesn't have an automatic fallback to PIO,
> even without my patch. A error return from omap_request_dma is
> propogated all the way back to the transfer request.
> The decision to use_dma (the variable) is unaltered.

OK, that might explain some nasty surprises then..

With these patches, does the driver still work in PIO mode though?

> Infact, it would be easier to implement a runtime fallback after
> this patch is
> merged as I have separated out the capability and runtime selection.
> (dma_caps and dma_in_use).

Sounds good to me, thanks for looking into it.

Regards,

Tony