Hi On Sat, Sep 26, 2015 at 8:01 PM, Geert Uytterhoeven <geert at linux-m68k.org> wrote: > Hi Alex, > > On Sat, Sep 26, 2015 at 7:07 PM, Alex Deucher <alexdeucher at gmail.com> > wrote: >> On Sat, Sep 26, 2015 at 4:28 AM, Geert Uytterhoeven >> <geert at linux-m68k.org> wrote: >>> On Thu, Sep 24, 2015 at 5:23 PM, Daniel Vetter <daniel at ffwll.ch> wrote: >>>> On Thu, Sep 24, 2015 at 02:46:21PM +0200, Thomas Petazzoni wrote: >>>>> Or are there some plans to make the writing of DRM drivers for very >>>>> simple/trivial devices a bit simpler? >>>> >>>> Since years I'm trying to sell someone on implementing support for >>>> drm_simple_outputs which would collapse the crtc->encoder->connector >>>> chain into 1 entity. Would be trivial to implement and then trivial to >>>> write simple drivers on top of that. And besides that drm already has >>>> piles of reallly simple drivers with just one output and one framebuffer. >>>> >>>> There's no reason not to use drm for gfx drivers at all. >>> >>> Good to hear that! >>> >>> For the (mailing list) record, can you please provide some explicit pointers >>> to these existing really simple drivers? >> >> See the tilcdc, ast, mgag200, and udl drivers for example. > > Thanks for the list! > > The smallest of these (udl) still counts in at ca. 2800 LoC, while there are > several fbdev drivers that have less than 200 LoC. > Granted, these really small ones support a single fixed video mode only, but > you can write a simple fbdev driver with mode setting in less than 1000 LoC. > > I'm sure DRM can do better?
Is counting lines really the level of the discussion to go here? DRM is a big set of helpers, nothing else. If many trivial, small drivers share common code, developers are more than welcome to contribute them to drm-core and help making drivers less complex. As Daniel mentioned, the connector+encoder+crtc combination is one of those simplifications that would make sense if more such drivers are added. Furthermore, the not-yet-merged SimpleDRM driver is one example how to implement multiple of those dumb-fb drivers with a shared code-base. Thanks David
