Re: [PATCH 3/4] arm64: dts: qcom: sdm845: Add missing MDSS reset

[Dmitry Baryshkov]

On Wed, Feb 18, 2026 at 12:18:39PM +0100, David Heidelberg wrote:
> On 18/02/2026 11:30, Konrad Dybcio wrote:
> > On 2/17/26 10:20 PM, Dmitry Baryshkov wrote:
> > > From: David Heidelberg <david@xxxxxxx>
> > > 
> > > If the OS does not support recovering the state left by the
> > > bootloader it needs a way to reset display hardware, so that it can
> > > start from a clean state. Add a reference to the relevant reset.
> > 
> > This is not the relevant reset
> > 
> > You want MDSS_CORE_BCR @ 0xaf0_2000
> 
> Thanks, I prepared the fixes [1].

UPD: touching that register resets the device. So, it seems, we will
have to live without the MDSS Core reset of SDM845.

> 
> I'll try to test it if it's not breaking anything for us and send as v2 of
> [2].
> 
> David
> 
> [1] https://codeberg.org/sdm845/linux/commits/branch/b4/mdss-reset
> [2] https://patchwork.kernel.org/project/linux-arm-msm/patch/20260112-mdss-reset-v1-1-af7c572204d3@xxxxxxx/
> 
> > 
> > Konrad
> > 
> > > 
> > > Signed-off-by: David Heidelberg <david@xxxxxxx>
> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > > ---
> > 
> > 
> > >   arch/arm64/boot/dts/qcom/sdm845.dtsi | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > > index bf2f9c04adba..75c192eddc57 100644
> > > --- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > > @@ -4550,6 +4550,7 @@ mdss: display-subsystem@ae00000 {
> > >   			reg-names = "mdss";
> > >   			power-domains = <&dispcc MDSS_GDSC>;
> > > +			resets = <&dispcc DISP_CC_MDSS_RSCC_BCR>;
> > >   			clocks = <&dispcc DISP_CC_MDSS_AHB_CLK>,
> > >   				 <&dispcc DISP_CC_MDSS_MDP_CLK>;
> > > 
> 
> -- 
> David Heidelberg
> 

-- 
With best wishes
Dmitry