Re: [PATCH] arm64: dts: qcom: sdm845-db845c: Mark cont splash memory region as reserved

[Dmitry Baryshkov]

On 31/01/2023 14:45, Konrad Dybcio wrote:
> On 31.01.2023 12:06, Dmitry Baryshkov wrote:
> > On Tue, 31 Jan 2023 at 12:54, Bryan O'Donoghue
> > <bryan.odonoghue@xxxxxxxxxx> wrote:
> > > On 24/01/2023 18:28, Amit Pundir wrote:
> > > > Put cont splash memory region under the reserved-memory
> > > > as confirmed by the downstream code as well.
> > > >
> > > > Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
> > > > ---
> > > >    arch/arm64/boot/dts/qcom/sdm845-db845c.dts | 8 ++++++++
> > > >    1 file changed, 8 insertions(+)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
> > > > index f41c6d600ea8..2ae59432cbda 100644
> > > > --- a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
> > > > +++ b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
> > > > @@ -100,6 +100,14 @@ hdmi_con: endpoint {
> > > >                };
> > > >        };
> > > >
> > > > +     reserved-memory {
> > > > +             /* Cont splash region set up by the bootloader */
> > > > +             cont_splash_mem: framebuffer@9d400000 {
> > > > +                     reg = <0x0 0x9d400000 0x0 0x2400000>;
> > > > +                     no-map;
> > > > +             };
> > > > +     };
> > > > +
> > > >        lt9611_1v8: lt9611-vdd18-regulator {
> > > >                compatible = "regulator-fixed";
> > > >                regulator-name = "LT9611_1V8";
> > >
> > > Doesn't this mean we loose 0x2400000 of DRAM for all rb3 platforms
> > > though ? About what 37 megabytes.. ?
> >
> > I think this memory is further used for display memory allocation. So
> > we are not loosing it, but dedicating it to the framebuffer memory.
> Not exactly, to do so, you'd have to use the memory-region property
> with mdss, which nobody does. Otherwise it's just a hole for Linux.

Then maybe it's time to start using that property?

> Konrad
> >

--
With best wishes
Dmitry