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

On 18/02/2026 13:19, Dmitry Baryshkov wrote:

On Wed, Feb 18, 2026 at 12:18:39PM +0100, David Heidelberg wrote:

quoted

On 18/02/2026 11:30, Konrad Dybcio wrote:

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On 2/17/26 10:20 PM, Dmitry Baryshkov wrote:

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From: David Heidelberg <david@ixit.cz>

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.

For me, so far, one test on Pixel 3 it freezes the device. Haven't found 
UART dongle, so not sure where exactly.

David

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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@ixit.cz/

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Konrad

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Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Dmitry Baryshkov <redacted>
---

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   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

-- 
David Heidelberg