Hi
On Sat, Sep 26, 2015 at 8:01 PM, Geert Uytterhoeven geert@linux-m68k.org wrote:
Hi Alex,
On Sat, Sep 26, 2015 at 7:07 PM, Alex Deucher alexdeucher@gmail.com wrote:
On Sat, Sep 26, 2015 at 4:28 AM, Geert Uytterhoeven geert@linux-m68k.org wrote:
On Thu, Sep 24, 2015 at 5:23 PM, Daniel Vetter daniel@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