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

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

[David Heidelberg via B4 Relay]

From: Casey Connolly <casey.connolly@linaro.org>

Stick it with the other default reserved regions, all sdm845 devices
use this address except for cheza.

Signed-off-by: Casey Connolly <casey.connolly@linaro.org>
Signed-off-by: David Heidelberg <david@ixit.cz>
---
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.

I would love to hear your opinions.

Thank you!
David
---
 arch/arm64/boot/dts/qcom/sdm845-samsung-starqltechn.dts      | 5 -----
 arch/arm64/boot/dts/qcom/sdm845-shift-axolotl.dts            | 5 -----
 arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama.dtsi        | 6 ------
 arch/arm64/boot/dts/qcom/sdm845-xiaomi-beryllium-common.dtsi | 6 ------
 arch/arm64/boot/dts/qcom/sdm845.dtsi                         | 5 +++++
 arch/arm64/boot/dts/qcom/sdm850.dtsi                         | 2 ++
 6 files changed, 7 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sdm845-samsung-starqltechn.dts b/arch/arm64/boot/dts/qcom/sdm845-samsung-starqltechn.dts
index 5d41a92cfebff..26f3081fb92aa 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-samsung-starqltechn.dts
+++ b/arch/arm64/boot/dts/qcom/sdm845-samsung-starqltechn.dts
@@ -109,11 +109,6 @@ vreg_s4a_1p8: pm8998-smps4 {
 	};
 
 	reserved-memory {
-		memory@9d400000 {
-			reg = <0x0 0x9d400000 0x0 0x02400000>;
-			no-map;
-		};
-
 		memory@a1300000 {
 			compatible = "ramoops";
 			reg = <0x0 0xa1300000 0x0 0x100000>;
diff --git a/arch/arm64/boot/dts/qcom/sdm845-shift-axolotl.dts b/arch/arm64/boot/dts/qcom/sdm845-shift-axolotl.dts
index ddc2b3ca3bc57..9adf0d76e3ae3 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-shift-axolotl.dts
+++ b/arch/arm64/boot/dts/qcom/sdm845-shift-axolotl.dts
@@ -62,11 +62,6 @@ key-vol-up {
 	};
 
 	reserved-memory {
-		framebuffer@9d400000 {
-			reg = <0x0 0x9d400000 0x0 (1080 * 2160 * 4)>;
-			no-map;
-		};
-
 		ramoops: ramoops@b0000000 {
 			compatible = "ramoops";
 			reg = <0 0xb0000000 0 0x00400000>;
diff --git a/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama.dtsi b/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama.dtsi
index 7dc9349eedfd9..f2d5585122590 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama.dtsi
@@ -119,12 +119,6 @@ vreg_s4a_1p8: pm8998-smps4 {
 	};
 
 	reserved-memory {
-		/* SONY was cool and didn't diverge from MTP this time, yay! */
-		cont_splash_mem: memory@9d400000 {
-			reg = <0x0 0x9d400000 0x0 0x2400000>;
-			no-map;
-		};
-
 		ramoops@ffc00000 {
 			compatible = "ramoops";
 			reg = <0x0 0xffc00000 0x0 0x100000>;
diff --git a/arch/arm64/boot/dts/qcom/sdm845-xiaomi-beryllium-common.dtsi b/arch/arm64/boot/dts/qcom/sdm845-xiaomi-beryllium-common.dtsi
index 785006a15e979..7e46e54dcf38c 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-xiaomi-beryllium-common.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845-xiaomi-beryllium-common.dtsi
@@ -100,12 +100,6 @@ spss_mem: memory@97f00000 {
 			no-map;
 		};
 
-		/* Cont splash region set up by the bootloader */
-		cont_splash_mem: framebuffer@9d400000 {
-			reg = <0 0x9d400000 0 0x2400000>;
-			no-map;
-		};
-
 		rmtfs_mem: memory@f6301000 {
 			compatible = "qcom,rmtfs-mem";
 			reg = <0 0xf6301000 0 0x200000>;
diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
index bf2f9c04adba7..7841959a43ca2 100644
--- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
@@ -890,6 +890,11 @@ mdata_mem: mpss-metadata {
 			no-map;
 		};
 
+		cont_splash_mem: framebuffer@9d400000 {
+			reg = <0 0x9d400000 0 0x2400000>;
+			no-map;
+		};
+
 		fastrpc_mem: fastrpc {
 			compatible = "shared-dma-pool";
 			alloc-ranges = <0x0 0x00000000 0x0 0xffffffff>;
diff --git a/arch/arm64/boot/dts/qcom/sdm850.dtsi b/arch/arm64/boot/dts/qcom/sdm850.dtsi
index da9f6fbe32f6c..b787575c77a5d 100644
--- a/arch/arm64/boot/dts/qcom/sdm850.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm850.dtsi
@@ -7,6 +7,8 @@
 
 #include "sdm845.dtsi"
 
+/delete-node/ &cont_splash_mem;
+
 &cpu4_opp_table {
 	cpu4_opp33: opp-2841600000 {
 		opp-hz = /bits/ 64 <2841600000>;

---
base-commit: 0c1c7a6a83feaf2cf182c52983ffe330ffb50280
change-id: 20251117-commonize-framebuffer-84f4feaa1f7a

Best regards,
-- 
David Heidelberg <david@ixit.cz>

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

[Konrad Dybcio]

On 11/17/25 1:27 PM, David Heidelberg via B4 Relay wrote:
> From: Casey Connolly <casey.connolly@linaro.org>
> 
> Stick it with the other default reserved regions, all sdm845 devices
> use this address except for cheza.
> 
> Signed-off-by: Casey Connolly <casey.connolly@linaro.org>
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---
> 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

Konrad

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@linaro.org>
> > 
> > Stick it with the other default reserved regions, all sdm845 devices
> > use this address except for cheza.
> > 
> > Signed-off-by: Casey Connolly <casey.connolly@linaro.org>
> > Signed-off-by: David Heidelberg <david@ixit.cz>
> > ---
> > 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