Subject: Re: [PATCH 2/2] powerpc/85xx: p1022ds: enable monitor switching via pixis indirect mode

From: Timur Tabi <[email-masked]>
Date: Thu, 17 Nov 2011 16:12:02 -0600

Scott Wood wrote:

>> This has the side-effect of no longer requiring U-Boot to enable the DIU.
>> Now Linux can enable the DIU all by itself.
> 
> Under what circumstances does Linux do this?  

p1022ds_set_monitor_port() is called by the DIU driver when it enables the DIU.  This happens on boot, for example, if you enable the framebuffer console.

> How does Linux prevent the
> NOR flash driver from binding to the device when this mode has been or
> will be used?

It doesn't.  This isn't a simple problem to solve.  On the P1022, NOR flash and the DIU are incompatible, and yet that's exactly what we ship on the P1022DS board.  We could just remove the NOR flash node from the DTS.

-- 
Timur Tabi
Linux kernel developer at Freescale