Re: [PATCH] i.MX23/28 framebuffer driver

On Wednesday 09 February 2011, Sascha Hauer wrote:

The driver patch itself is Cced to linux-fbdev, only the introductory
mail is not.

Ok, I see.

quoted

Did you consider making the driver a KMS driver instead of
a frame buffer? I think the recommendation these days is
to start out with KMS for new drivers, which will be somewhat
simpler and give you a frame buffer device as well. I don't
think that there is a need to change over any drivers from
fb to kms though, since you've already done the work.

I tried doing so for the i.MX51 which supports multiple displays on dvi
and vga outputs and thus could make good use of KMS and friends. Anyway,
I got stuck quite fast. The KMS stuff is tightly coupled with DRM/DRI
and needs many many callbacks to implement. Additionally the userspace
tools expect a nvidia/amd/intel driver and do not have a generic
fallback. I think this stuff is good for implementing a full blown
graphics driver, but is lacking support for simple framebuffer grapics.
I'd love to go this way but it still requires a lot of work.

Ok. This sounds like a lot of upfront work indeed, to make KMS more
generic, though I think a number of driver would benefit from it
eventually. It could be something for the Linaro graphics working
group to look at in the following 11.11 release, depending on how
many other people are interested in getting there.

	Arnd