Re: [PATCH v2 5/5] drm/ingenic: Add option to alloc cached GEM buffers

Paul Cercueil
2021-03-12T11:53:12Z

Le jeu. 11 mars 2021 à 12:30, Christoph Hellwig <hch@infradead.org> a
écrit :
> On Sun, Mar 07, 2021 at 08:28:35PM +0000, Paul Cercueil wrote:
>> With the module parameter ingenic-drm.cached_gem_buffers, it is
>> possible
>> to specify that we want GEM buffers backed by non-coherent memory.
>
> Shouldn't there be a way to discover this through a DT property?

Good question. My original way of thinking was that as this feature
speeds up only software rendering, this is really
application-dependent: a modern desktop where everything is rendered
via the GPU wouldn't benefit much from it. With that in mind, it is
fine as a module option.

On the other hand... the "software rendering is faster with
non-coherent buffers" really is a SoC property, since it is only true
for some generations of Ingenic SoCs and not others. So it would make
sense to have a DT property for it.

-Paul