On Wed, Apr 8, 2015 at 4:17 PM, Rob Herring <robherring2@xxxxxxxxx> wrote:
>> Then we have dma controllers needing to be registered at subsys_initcall() for obvious reasons.
>
> These should be fixable with deferred probe. That requires fixing all
> the client drivers where as fixing the dependencies would not need
> driver changes.
DMA is tricky in that there are three cases, not two:
1. DMA engine is available,
2. DMA engine is not yet available (e.g. DMA engine driver is modular),
3. DMA engine will never be available (DMA engine or DMA engine driver
not available).
Case 2 is the tricky one: probably you don't want the client driver to
fail hard,
but want to fall back to PIO, and try to setup DMA again later.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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