Re: [PATCH] MAINTAINERS: Add Helge as fbdev maintainer

[Gerd Hoffmann <kraxel@redhat.com>]

On Mon, Jan 17, 2022 at 02:29:47PM +0100, Geert Uytterhoeven wrote:
> Hi Gerd,
> 
> On Mon, Jan 17, 2022 at 1:57 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
> > > b) to include new drivers (for old hardware) if they arrive (probably happens rarely but there can be).
> > >    I know of at least one driver which won't be able to support DRM....
> >
> > Hmm?  I seriously doubt that.  There is always the option to use a
> > shadow framebuffer, then convert from standard drm formats to whatever
> > esoteric pixel format your hardware expects.
> >
> > Been there, done that.  Have a look at the cirrus driver.  The physical
> > hardware was designed in the early 90-ies, almost 30 years ago.  These
> > days it exists in virtual form only (qemu emulates it).  Thanks to the
> > drm driver it runs wayland just fine even though it has a bunch of
> > constrains dictated by the hardware design.
> 
> The Cirrus DRM driver supports TrueColor (RGB565/888 and ARGB8888)
> modes only.  The Cirrus fbdev driver also supports mochrome and 256
> color modes.
> 
> There exist some DRM drivers that do support DRM_FORMAT_C8, but none of
> the "tiny" ones do. Same for DRM_FORMAT_RGB{332,233}.

Adding that to the cirrus driver shouldn't be hard.  I'm wondering
whenever there are any userspace apps which would actually use that
though.

take care,
  Gerd