Re: No more new fbdev drivers, please

[Noralf TrÃnnes]

Den 27.09.2015 18:08, skrev Emil Velikov:
> Hi all,
>
> On 27 September 2015 at 14:09, Noralf TrÃnnes <noralf@xxxxxxxxxxx> wrote:
> > Den 24.09.2015 14:27, skrev Tomi Valkeinen:
> > > Hi all,
> > >
> > > fbdev is (more or less) maintained, but it's a deprecated framework. All
> > > new Linux display drivers should be done on DRM.
> > >
> > > So let's not add any more new fbdev drivers.
> > >
> > > I will continue to maintain the current fbdev drivers, and I don't mind
> > > adding some new features to those current drivers, as long as the amount
> > > of code required to add the features stays sensible.
> > >
> > > I see we have three fbdev drivers in staging: xgifb, fbtft and sm750fb,
> > > and the question is what to do with those.
> > >
> > > xgifb was added in 2010, and is still in staging.
> > >
> > > fbtft looks like maybe some kind of framework on top of fbdev, with
> > > fbtft specific subdrivers... I didn't look at it in detail, but my gut
> > > says "never".
> >
> > I have done some work [1] to try and make fbtft look more like the rest
> > of the kernel (doc [2]), but that work will result in an almost complete
> > rewrite of fbtft.
>  From a very quick skim fbtft looks pretty much like drm/panel. We
> presently have 30+ 'simple' dsi panels, plus a bunch of spi ones. Have
> you had a look at these ?

Thanks, that was useful.
I can use drm_panel to setup the controller (prepare) and do backlight
(enable/disable), but I need a way to send framebuffer changes.
I could do this:

struct tinydrm_panel_funcs {
        int (*update)(struct drm_framebuffer *fb,
                      struct drm_gem_cma_object *cma_obj,
                      unsigned flags, unsigned color,
                      struct drm_clip_rect *clips, unsigned num_clips);
};

struct tinydrm_panel {
        struct drm_panel panel;
        u32 width;
        u32 height;
        void *dev_private;

        const struct tinydrm_panel_funcs *funcs;
};

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