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

From: Arun Ramamurthy
Date: Mon Mar 02 2015 - 14:10:11 EST

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:
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).

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