On Thu, Nov 16, 2023 at 07:07:37PM +0100, Javier Martinez Canillas wrote: > This is used to specify the page start address offset of the display RAM. > > The value is used as offset when setting the page start address with the > SSD130X_SET_PAGE_RANGE command, and the driver currently sets its value to > 1 if the property is not present in the Device Tree. > > But the datasheet mentions that the value on reset for the page start is a > 0, so it makes more sense to also have 0 as the default value for the page > offset if the property is not present. > > In fact, using a default value of 1 leads to the display not working when > the fbdev is attached to the framebuffer console. > > Reported-by: Sahaj Sarup <sahaj.sarup@xxxxxxxxxx> > Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> > --- > > .../devicetree/bindings/display/solomon,ssd1307fb.yaml | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml > index 3afbb52d1b7f..badd81459aaa 100644 > --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml > +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml > @@ -35,7 +35,7 @@ properties: > > solomon,page-offset: > $ref: /schemas/types.yaml#/definitions/uint32 > - default: 1 > + default: 0 I think I saw it pointed out by Maxime elsewhere that this breaks the ABI. It would be nice if DT defaults matched the hardware's, but I don't really think it is worth breaking the ABI here. Expanding the property description to explain the impact of the particular values might help with incorrect usage. Thanks, Conor. > description: > Offset of pages (band of 8 pixels) that the screen is mapped to > > -- > 2.41.0 >
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