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

[Paul Cercueil]

Le jeu. 11 mars 2021 à 12:30, Christoph Hellwig <hch@xxxxxxxxxxxxx> 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