[PATCH] [RFC PATCH] DRM: add DRM Driver for Samsung SoC EXYNOS4210.

Alan Cox alan at lxorguk.ukuu.org.uk
Wed Aug 3 11:54:24 PDT 2011

> if so, I am aware of it but his patch isn't applied to drm-next yet and 
> so my drm driver doesn't include his patch. of course I will reuse it 
> and remove the samsung_ namespace as you pointed out if the patch is 
> applied to drm-next.

It would be nice it was as its also the same as the code being carried in
the GEM glue for the gma500 driver so we now have 3 users (plus i915 can
use it).

I agree with Sascha Hauer that a lot more could be shared with other
(particularly future 'dumb') drivers. I think however it would be better
to see what wants moving *after* such drivers are merged rather than
guess in advance and do unneeded work and get it wrong anyway.

It's a nice reference driver for anyone else writing a DRM driver too.

Architecturally it's actually not quite as neat a fit for PC dumb devices
as it might first seem though - in the PC world framebuffer case for a lot
of cards I suspect you actually want to use real GEM objects.

In the PC case you do get multiple framebuffers allocated not all of
which are in use so for cards with limited memory a true GEM object is
useful. This would then be 'pinned' and 'unpinned' by copying it
to/from video RAM and invalidating the mappings so mmap users fault with
the new address next access)

With that behaviour proper use can be made of video RAM and out of use
objects can still be paged.

For other cases it looks right as is.


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