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Subject: Re: No more new fbdev drivers, please
From: Gerd Hoffmann <kraxel@redhat.com>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: David Herrmann <dh.herrmann@gmail.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
        linux-fbdev <linux-fbdev@vger.kernel.org>,
        Teddy Wang <teddy.wang@siliconmotion.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        DRI Development <dri-devel@lists.freedesktop.org>,
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        Tomi Valkeinen <tomi.valkeinen@ti.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dave Airlie <airlied@redhat.com>,
        Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Date: Tue, 29 Sep 2015 10:23:23 +0200
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On Mo, 2015-09-28 at 14:36 +0200, Daniel Vetter wrote:
> On Mon, Sep 28, 2015 at 09:39:13AM +0200, Gerd Hoffmann wrote:
> >   Hi,
> > 
> > > As Daniel mentioned, the connector+encoder+crtc combination is one of
> > > those simplifications that would make sense if more such drivers are
> > > added.
> > 
> > Another one is memory management.  It's pretty complex because it can
> > handle _way_ more than what simple drivers need, and the result is
> > _alot_ of ttm boilerplate in the drivers.
> 
> ttm is pretty impressive overkill for most simplistic drm drivers. If you
> just need contiguous framebuffers for display then the cma helpers should
> take care of pretty much all the boilerplate for you. They have ready-made
> simple gem and dumb framebuffer mmap support, which is all a basic kms
> driver needs.

Does that work on !arm meanwhile?  Last time I checked (when writing
bochsdrm, around v3.14) the cma helpers didn't even build on x86 ...

cheers,
  Gerd