[PATCH v2 0/6] BCM2835 / simple framebuffer support

Andre Heider a.heider at gmail.com
Wed Nov 6 12:40:49 EST 2013

Hi Sascha,

On Wed, Nov 06, 2013 at 10:46:28AM +0100, Sascha Hauer wrote:
> Hi Andre,
> On Tue, Nov 05, 2013 at 12:00:58AM +0100, Andre Heider wrote:
> > This is v2 of my patch set posted on 10/24.
> > It adds framebuffer support for the RPi and provides an additional config
> > knob to set up the kernel's simplefb driver. The active barebox framebuffer
> > is basis for that feature, so that other platforms can make use of it.
> > 
> > This simplefb option depends on the bcm2835 fb driver since drivers need
> > to be aware of simplefb: framebuffers need to stay configured and cannot be
> > teared down.
> > 
> > The RPi case is rather simple in this regard. The allocated framebuffer lies
> > within the memory range of the VideoCore of the ARM/VC memory split. Hence,
> > there is no memory range that needs to be reserved as far as the ARM side
> > of things is concerned.
> > This likely needs to be added once other fb driver want to use simplefb.
> > 
> > Changes since v1:
> > * renamed "pitch" to "line_length" to match the kernel
> > * the bcm2835 framebuffer driver is now standalone
> > * configuring simplefb for the kernel is based on the active barebox
> >   framebuffer
> I applied this series without the simplefb patch.


> For the simplefb I'd like to use the following patch instead. It's your
> patch with some adjustments:
> - add a register_simplefb device parameter to make it configurable
>   whether a simplefb node should be created or not.
> - register the OF fixup in register_framebuffer(). This way we always
>   have a simplefb node once a framebuffer is registered without getting
>   spurious warnings when there is no framebuffer present.
> - check if the framebuffer is actually enabled. If it's not, we
>   shouldn't register a simplefb node.
> Are you fine with this and if yes, could you give the patch a test?
> It depends on the add-context-pointer-to-of_register_fixup patch I just
> posted. Just try the current -next branch, it should contain all you
> need for testing.

Neat, that looks nicer, so no objection here ;)

And yes, it works if I set fb0.enable=1 and fb0.register_simplefb=1,
both are 0 per default.

Now I wonder who/where those are supposed to get set? Is that a job for
the runtime environment?

I didn't really care about the enabled parameter until now, there isn't
anything to do in the fb_enable callback for this fb driver and `splash`
doesn't seem to care either.


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