Regression in Linux next with dma cma changes

Regression in Linux next with dma cma changes

[Tony Lindgren]

Hi,

Looks like commit d222e42e8816 ("dma-contiguous: do not allocate a
single page from CMA area") caused a regression at least for
omap dss where we now get the following error on init:

omapdss_dispc 58001000.dispc:
dispc_errata_i734_wa_init: dma_alloc_writecombine failed

Any ideas what might be going wrong?

Regards,

Tony

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Re: Regression in Linux next with dma cma changes

[Nicolin Chen]

On Tue, Feb 26, 2019 at 12:01:55PM -0800, Tony Lindgren wrote:
> Looks like commit d222e42e8816 ("dma-contiguous: do not allocate a
> single page from CMA area") caused a regression at least for
> omap dss where we now get the following error on init:
> 
> omapdss_dispc 58001000.dispc:
> dispc_errata_i734_wa_init: dma_alloc_writecombine failed
> 
> Any ideas what might be going wrong?

It's probably because the dma_alloc_from_contiguous() call in
this path doesn't rebound to allocate a normal single page.

And I guess we should have left the change within dma-direct.

Christoph, do you agree?

I am submitting a revert first.

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