Arch Linux

Bednar

Member

Registered: 2015-09-19

Posts: 72

[SOLVED]grub boot parameter ignored

Hi all,

I was trying to enable the overdrive functionality on my VEGA 64 so I added the following kernel parameter to GRUB:

/etc/default/grub:

GRUB_DEFAULT="Arch Linux Latest"
GRUB_TIMEOUT="5"
GRUB_DISTRIBUTOR="Arch"
GRUB_CMDLINE_LINUX_DEFAULT="quiet amdgpu.ppfeaturemask=0xfffd7fff"
GRUB_CMDLINE_LINUX=""

Then I updated grub and rebooted the machine:

printf "0x%08x\n" $(cat /sys/module/amdgpu/parameters/ppfeaturemask)

Returns 0xfffd3fff.

Is the overdrive functionality on now?

Thanks,

B

Last edited by Bednar (2019-04-06 09:43:29)

loqs

Member

Registered: 2014-03-06

Posts: 17,369

Re: [SOLVED]grub boot parameter ignored

https://git.kernel.org/pub/scm/linux/ke … red.h#n129
0xFFFD3FFF & 0x4000 = 0

Bednar

Member

Registered: 2015-09-19

Posts: 72

Re: [SOLVED]grub boot parameter ignored

I understand that means it isn't. Why is the ppfeaturemask not updated in accordance with the boot parameter set, though?

Thanks.

Bednar

Member

Registered: 2015-09-19

Posts: 72

Re: [SOLVED]grub boot parameter ignored

Ok, I figured it out. It turns out modifying /etc/default/grub only applied to the linux-lts image. I had to add the kernel parameter manually during Boot to the latest kernel's image.

Thanks

Last edited by Bednar (2019-04-06 09:43:52)