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

From	Daniel Vetter <daniel@ffwll.ch>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 0/3] staging: remove fbdev drivers
Date	2016-12-09 14:40 +0100
Message-ID	<sMtz4-3Rh-21@gated-at.bofh.it> (permalink)
References	(5 earlier) <sM8NY-7L9-73@gated-at.bofh.it> <sMeA1-2TA-1@gated-at.bofh.it> <sMeTo-30n-17@gated-at.bofh.it> <sMoSJ-Zv-1@gated-at.bofh.it> <sMrQC-2JA-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Fri, Dec 09, 2016 at 10:44:16PM +1100, Benjamin Herrenschmidt wrote:
> On Fri, 2016-12-09 at 09:34 +0100, Daniel Vetter wrote:
> > 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.

Yeah, if you wire up the dma_alloc_coherent to cma you'll get a contiguous
buffer pinned into place.

> > So it is possible, only reason vram dumb buffers look worse is that there's
> > only 3 and no one cares about them, vs about 20 and a very active community
> > of contributors (also for core drm improvements) for the other case.
> 
> Well, we could move offb to drm while at it I suppose that would be another
> one (offb is the "dumb driver based on pre-programmed output by firmware).

One of the still in-flight drm drivers is the simpledrm thing meant for
all kinds of firmware drivers like efifb and similar things on arm for
pre-programmed output set up by firmware. I.e. no modeset support and
otherwise a lot of fake to make it work as drm driver, but the idea that
it's good enough until your real drm driver takes over.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Thread

Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-08 02:10 +0100
  Re: [RFC PATCH 0/3] staging: remove fbdev drivers Tomi Valkeinen <tomi.valkeinen@ti.com> - 2016-12-08 09:10 +0100
    Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-08 22:30 +0100
      Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-08 22:50 +0100
        Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-09 09:20 +0100
  Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-08 11:20 +0100
    Re: [RFC PATCH 0/3] staging: remove fbdev drivers Geert Uytterhoeven <geert@linux-m68k.org> - 2016-12-08 13:20 +0100
      Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-08 15:20 +0100
        Re: [RFC PATCH 0/3] staging: remove fbdev drivers Geert Uytterhoeven <geert@linux-m68k.org> - 2016-12-08 15:30 +0100
          Re: [RFC PATCH 0/3] staging: remove fbdev drivers Thomas Petazzoni <thomas.petazzoni@free-electrons.com> - 2016-12-08 15:40 +0100
            Re: [RFC PATCH 0/3] staging: remove fbdev drivers Geert Uytterhoeven <geert@linux-m68k.org> - 2016-12-08 15:50 +0100
              Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-08 16:30 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-08 22:40 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-08 23:00 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-09 09:40 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-09 09:50 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-09 12:50 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-09 14:40 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-09 22:20 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-09 12:50 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Geert Uytterhoeven <geert@linux-m68k.org> - 2016-12-09 13:40 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Lucas Stach <l.stach@pengutronix.de> - 2016-12-09 14:20 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-09 14:40 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers David Herrmann <dh.herrmann@gmail.com> - 2016-12-09 15:00 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-09 15:10 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-09 21:40 +0100
                Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-09 09:40 +0100
          Re: [RFC PATCH 0/3] staging: remove fbdev drivers Jani Nikula <jani.nikula@linux.intel.com> - 2016-12-08 16:10 +0100
        Re: [RFC PATCH 0/3] staging: remove fbdev drivers Daniel Vetter <daniel@ffwll.ch> - 2016-12-08 15:30 +0100
    Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-08 23:40 +0100
      Re: [RFC PATCH 0/3] staging: remove fbdev drivers Dave Airlie <airlied@gmail.com> - 2016-12-09 01:10 +0100
        Re: [RFC PATCH 0/3] staging: remove fbdev drivers Geert Uytterhoeven <geert@linux-m68k.org> - 2016-12-09 09:10 +0100
        Re: [RFC PATCH 0/3] staging: remove fbdev drivers Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-12-09 12:50 +0100

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