Re: [RFC PATCH 0/3] staging: remove fbdev drivers

Am Freitag, den 09.12.2016, 22:44 +1100 schrieb Benjamin Herrenschmidt:

On Fri, 2016-12-09 at 09:34 +0100, Daniel Vetter wrote:

quoted

Yeah if you have discrete vram then your dumb display driver isn't all
that pretty. We essentially just have the few drivers Dave hacked up to be
able to boot some servers. And there's definitely lots of room for more
shared code for those, and also some better infrastructure and helpers to
share more cod and make them better.

The massive pile of dumb framebuffers we all merged over the past 2 years
all use system/dma memory for scanout, and for those we have the very nice
cma helpers that take care of everything for you. 

Do they work if the system/DMA memory has to be physically contiguous
and at a fixed address ? The AST "ARM side" GPU is like that.

Yes, CMA is exactly the solution for that. It provides contiguous memory
that doesn't need to be removed from the normal Linux memory handling
and allows for the CMA region to be at specific places if needed. It's
just a matter of describing the constraints properly.

Regards,
Lucas