How to disable Spread Spectrum Clocking(SSC) on Orin

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
1

The driver package we use is Jetson Linux 34.1.1
The pcie controller is c5 root port(0x141a0000)

3

Our team will do the investigation and provide suggestions soon. Thanks

4

Ok. Thank you for your reply.

6

Please use the below patch to disable spread for PLLE, NVHS, and GBE PLLs

diff --git a/include/parts/uphy/3701-0000-3737-0000-uphy.dtsi b/include/parts/uphy/3701-0000-3737-0000-uphy.dtsi
index 4eb42bd..6226a9d 100644
--- a/include/parts/uphy/3701-0000-3737-0000-uphy.dtsi
+++ b/include/parts/uphy/3701-0000-3737-0000-uphy.dtsi
@@ -32,4 +32,21 @@
 		gbe-uphy-config = <22>;
 		gbe0-enable-10g;
 	};
+
+	clocks {
+		clock@plle {
+			clk-id = <TEGRA234_CLK_PLLE>;
+			disable-spread = <1>;
+		};
+
+		clock@pllnvhs {
+			clk-id = <TEGRA234_CLK_PLLNVHS>;
+			disable-spread = <1>;
+		};
+
+		clock@pllgbe {
+			clk-id = <TEGRA234_CLK_PLLGBE>;
+			disable-spread = <1>;
+		};
+	};
 };
1 Like
7

We will try it.
Thanks.

8

where can i find 3701-0000-3737-0000-uphy.dtsi?

9

It should be at $TOP/platform/bpmp-t23x/ location

10

Hi,

The code of this is not public. Please use dtc tool to convert your bpmp dtb under Linux_for_Tegra/bootloader back to dts and add what vidyas shared.

11

Ok,thanks

13

@WayneWWW: I’m also looking for the dtb in the JetPack 5.0 BSP binary, but under Linux_for_Tegra/bootloader there is no dtb regarding bpmp or uphy. In the BSP source, I also couldn’t find the dtsi that @vidyas suggested or any dtsi that contains the entries like ‘gbe0-enable-10g’. Could you please tell me exactly which dtb I should look for? Thanks!

14

You can try to add * to your search.

/Linux_for_Tegra/bootloader$ find -iname "*bpmp*.dtb"
./t186ref/tegra194-a02-bpmp-p2888-a02.dtb
./t186ref/tegra194-a02-bpmp-p2888-0005-a04.dtb
./t186ref/tegra194-a02-bpmp-p2888-a01.dtb
./t186ref/tegra234-bpmp-3701-0000-as-3767-0000-3737-0000.dtb
./t186ref/tegra234-bpmp-3701-0000-as-3767-0010-3737-0000.dtb
./t186ref/tegra194-a01-bpmp-p2888-a01.dtb
./t186ref/tegra234-bpmp-3701-0000-as-3701-0004-3737-0000.dtb
./t186ref/tegra194-a01-bpmp-p2888-a02.dtb
./t186ref/tegra194-a02-bpmp-p2888-0004-a04-mccoy.dtb
./t186ref/tegra194-a02-bpmp-p2888-0008-b01-jaxi.dtb
./t186ref/tegra194-a02-bpmp-p2888-0005-a04-maxn.dtb
./t186ref/tegra194-a02-bpmp-p2888-0008-b01-jaxi-noecc.dtb
./t186ref/tegra234-bpmp-3701-0000-3737-0000-maxn.dtb
./t186ref/tegra234-bpmp-3701-0000-3737-0000.dtb
./t186ref/tegra194-a02-bpmp-p2888-a04-maxn.dtb
./t186ref/tegra194-a02-bpmp-p2888-a04.dtb
./t186ref/tegra194-a02-bpmp-p3668-a00.dtb
15

I see, they reside in the sub-directory. Thank you for the prompt answer!

1 Like
16

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