Linux/AM3358: How to power off the SGX (Graphics unit ) using Linux?

sarfaraz shaikh

Part Number: AM3358

Tool/software: Linux

I want to have a controller with minimum power consumption. I am not using the SGX GPU. So I want to turn off the power to that unit in controller. How Can I do that .

over 6 years ago

0 Pavel Botev over 6 years ago

TI__Guru**** 170625 points

Hi Sarfaraz,

You can directly write to the SGX power registers, as below doc suggest:

www.ti.com/.../sprac74a.pdf
4.2 OptimizationsUsedfor LowPowerUse Cases
4.2.3 Graphics(SGX)

For more info check also:

AM335x TRM, section 8.1.13.7 PRM_GFX Registers

e2e.ti.com/.../662287

Regards,
Pavel

0 sarfaraz shaikh over 6 years ago in reply to Pavel Botev

Expert 1526 points

Thanks Pavel. This document shows how to turn OFF the GPU.
Is there any method to kepp it OFF by default without using the devmem tools?

0 Pavel Botev over 6 years ago in reply to sarfaraz shaikh

TI__Guru**** 170625 points

Sarfaraz,

You can try to change the sgx status from enable to disable in main DTS file. For example AM335x EVM comes with SGX enabled by default, and this is done in below file and line:

linux-kernel/arch/arm/boot/dts/am335x-evm.dts

&sgx {
status = "okay";
};

If this change stops only SGX clock (you can check this in the SGX power status register), then you should also modify below files where SGX power is enabled:

linux-kernel/arch/arm/mach-omap2/powerdomains33xx_data.c
linux-kernel/arch/arm/mach-omap2/pm33xx-core.c

Regards,
Pavel

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Linux/AM3358: How to power off the SGX (Graphics unit ) using Linux?