Re: [PATCH RFC] arm64: dts: qcom: sdm845: add framebuffer reserved memory

[Dmitry Baryshkov]

On Tue, Nov 18, 2025 at 01:26:17PM +0100, Konrad Dybcio wrote:
> On 11/17/25 1:27 PM, David Heidelberg via B4 Relay wrote:
> > From: Casey Connolly <casey.connolly@xxxxxxxxxx>
> > 
> > Stick it with the other default reserved regions, all sdm845 devices
> > use this address except for cheza.
> > 
> > Signed-off-by: Casey Connolly <casey.connolly@xxxxxxxxxx>
> > Signed-off-by: David Heidelberg <david@xxxxxxx>
> > ---
> > What do you think about this proposed change?
> > 
> > I assume QCOM recommends or by default use the default memory region,
> > but as can be seen on cheza or sdm850, it seems that vendor can customize
> > the region, thus it's not guranteed to have it always on the same address.
> > 
> > There are two approaches I see:
> > 1. keep as is defined in each device-tree frambuffer node
> > 2. commonize frambuffer node to sdm845.dtsi and in case of exception
> >    remove the node and definite it in device-tree.
> 
> Generally this carveout is useful only if you use the bootloader-
> initiated framebuffer. Post that, drm/msm allocates its own

Previously carveout could have been used for FB memory, but with the
switch to GPUVM I think we lost that ability.

-- 
With best wishes
Dmitry