[PATCH 2/3] drm: imx: Move imx-drm driver out of staging

[Philipp Zabel]

Am Dienstag, den 04.11.2014, 16:19 +0000 schrieb Emil Velikov:
> Hi Philipp,
> 
> Just a flyby question
> 
> On 04/11/14 10:52, Philipp Zabel wrote:
> > The imx-drm driver was put into staging mostly for the following reasons,
> > all of which have been addressed or superseded:
> >  - convert the irq driver to use linear irq domains
> >  - work out the device tree bindings, this lead to the common of_graph
> >    bindings being used
> Afaics Steve's patches introduce some non-backward compatible changes to
> the DT bindings (s/port/crtc/). Shouldn't those be discussed/resolved
> prior to pushing the driver out of staging ?

Those binding changes are backwards. We moved away from mentioning crtcs
in the device tree earlier, as those are most definitely not a property
of the hardware.
The two output ports of the IPU in the device tree correspond to the
physical output signals of the two DIs, not to the crtcs, which are a
linux specific abstraction, more closely related to parts of the DP and
DC units.

What is exactly represented by each crtc could be changed in the code
without affecting the device tree bindings. In hardware, it is possible
to link both of the DC/DP output channels to either DI dynamically.
The driver could be changed to stop associating each crtc with a fixed
DI, and select the appropriate DI automatically for a given crtc <->
encoder pair.

In my opinion the time for non-backward compatible changes has passed
anyway. That being said, if a case is to be made for device tree
changes, it should be discussed before the move.

regards
Philipp