Re: [PATCH] video: ARM CLCD: Added support for FBIOPAN_DISPLAY and virtual y resolution

On 15-03-02 08:11 AM, Russell King - ARM Linux wrote:

On Mon, Mar 02, 2015 at 04:08:29PM +0000, Pawel Moll wrote:

quoted

I'm not sure about this... The word "virtual" never works well with
device tree nodes defined as "hardware description".

I understand what you're doing, but adding this property to the display
controller's node doesn't sound right. How does this describe hardware?
If anywhere, it's more like a job for the panel node?

I see what you are saying Pawel, I can follow Russell's recommendation 
of adding a RAM size node called max-memory-available or something similar

A better description (and implementation) would be to describe the size
of the RAM available for video purposes.  The driver can then use the
requested virtual X resolution to limit (and/or compute) the virtual Y
resolution to allow Y panning/wrapping of the display.

In this scenario, where would I specify the virtual X resolution? I am 
assuming it would be in the panel-timing node as Pawel suggested?

This would match some hardware where the video RAM is indeed a separate
physical set of RAM (such as the IM-PD/1).