On 22/01/2023 15:36, Rob Herring wrote:

On Sat, Jan 21, 2023 at 9:36 AM Rayyan Ansari [off-list ref] wrote:

quoted

Why do you need this change?

The 'simple-framebuffer' contains data on how the bootloader
configured the display. The bootloader doesn't configure the display
size, so this information doesn't belong here. The information should
already be in the panel node, so also no point in duplicating it here.

quoted

Signed-off-by: Rayyan Ansari <redacted>
---
  .../devicetree/bindings/display/simple-framebuffer.yaml   | 8 ++++++++
  1 file changed, 8 insertions(+)

Hi Rob,

There is the usecase that Hans has mentioned, but I have also mentioned 
another usecase previously.

Adding the width-mm and height-mm properties allows user interfaces such 
as Phosh (https://puri.sm/posts/phosh-overview/) to scale correctly to 
the screen. In my case, a panel node is not available and the 
aforementioned interface is in fact running on the SimpleDRM driver 
(which binds to the simple-framebuffer device).

Here is the device I have tested this patch on, the Lumia 735 phone: 
https://wiki.postmarketos.org/images/c/c3/Lumia_735_Phosh.png
Without this patch, this would appear quite small on the screen.

See https://patchwork.freedesktop.org/patch/519107/?series=113053&rev=1 
for some background info about this patch.

Regards,
-- 
Rayyan Ansari
https://ansari.sh