Re: No more new fbdev drivers, please

Hi,

fbdev is (more or less) maintained, but it's a deprecated framework. All
new Linux display drivers should be done on DRM.

What about no-mmu platforms? DRM has a big fat MMU dependency in the 
kconfig, is there a way to write DRM driver for such devices?

/Kamil

On 25/09/15 13:41, Kamil Lulko wrote:

Hi,

quoted

fbdev is (more or less) maintained, but it's a deprecated framework. All
new Linux display drivers should be done on DRM.

What about no-mmu platforms? DRM has a big fat MMU dependency in the
kconfig, is there a way to write DRM driver for such devices?

I guess not.

Then again, I don't see why DRM would have a hard dependency to MMU, if
the work is done to make DRM work optionally without MMU. How much work
that is, I have no idea.

 Tom

On Fri, Sep 25, 2015 at 04:09:46PM +0300, Tomi Valkeinen wrote:

On 25/09/15 13:41, Kamil Lulko wrote:

quoted

Hi,

quoted

fbdev is (more or less) maintained, but it's a deprecated framework. All
new Linux display drivers should be done on DRM.

What about no-mmu platforms? DRM has a big fat MMU dependency in the
kconfig, is there a way to write DRM driver for such devices?

I guess not.

Then again, I don't see why DRM would have a hard dependency to MMU, if
the work is done to make DRM work optionally without MMU. How much work
that is, I have no idea.

We have plenty drivers in drm without hw mmu, and yeah there's probably no
reason at all why the drm subsystem has a hard depency on cpu MMUs. Might
be some #ifdef fallout that needs to be done, but there shouldn't be
anything fundamental. Maybe the old dri1 days code has something, but
that's all historical cruft anyway.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

On Fri, Sep 25, 2015 at 12:41 PM, Kamil Lulko [off-list ref] wrote:

quoted

fbdev is (more or less) maintained, but it's a deprecated framework. All
new Linux display drivers should be done on DRM.

What about no-mmu platforms? DRM has a big fat MMU dependency in the
kconfig, is there a way to write DRM driver for such devices?

That would indeed be a showstopper...

I dropped the dependency, and gave it a quick try for m68knommu.
Seems like DRM currently needs pgprot_writecombine() and pte_wrprotect().
Probably that can be fixed easily.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds