[U-Boot] [PATCH 1/2] i.MX: mxc_ipuv3_fb: add ipuv3_fb_shutdown() routine to stop IPU before bootm

[Sascha Hauer]

On Sun, Sep 23, 2012 at 07:27:41PM +0200, Stefano Babic wrote:
> 
> > 
> > I would like to see a handoff of display settings from U-Boot to
> > the kernel, but that's also a tricky thing as long as we're supporting
> > different mechanisms (DT in main-line and kernel parameters in
> > older kernels).
> 
> Yes, and a lot of other things. I know Anatolji implemented this
> behavior for a PPC5121, but we cannot generalize. I agree that the
> handoff is difficult and not maintainable. My question is different: if
> the IPU drivers in kernel are compiled as modules, and I will load them
> only after booting, and the framebuffer's memory is reserved so that the
> kernel does not touch it, is there still a known reason because the IPU
> should not run when we boot the kernel? I know this issue with USB,
> maybe we have now the same with the IPU.

The clock framework disables all unused clocks in a late_initcall. when
the IPU is compiled as a module, the IPU clock will be one of those.

Sascha


-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |