amdgpu and custom kernels

HiImTye · 2017-07-09 07:23:55

so I tried my Google-fu and failed on this subject. I tried the linux-zen kernel on my PC last night, and noticed a marked improvement, with the only caveat that I had to install the nvidia-dkms module because X obviously wouldn't load. my laptop, on the other hand, uses amdgpu and the opencl-amd drivers. there's no amdgpu-dkms in the repos, nor is there any in the AUR, so how does one use the open source amdgpu drivers with a custom kernel?

Last edited by HiImTye (2017-07-09 07:25:17)

Taijian · 2017-07-09 09:34:05

amdgpu is a kernel module. It is therefore compiled as a module for all kernels in the arch repository. You do not need to do anything other than install the kernel and boot it.

Last edited by Taijian (2017-07-09 09:34:18)

Lone_Wolf · 2017-07-09 11:13:11

amdgpu is an in-kernel module, whether it's present in a kernel depends solely on the kernel build configuration .

DKMS is only needed for out-of-tree kernel modules, like those from nvidia and virtualbox.

HiImTye · 2017-07-09 23:52:28

strange, when I booted on my PC, there was no nvidia module in linux-zen (I had to use nvidia-dkms), nor is there amdgpu in linux-zen on the laptop (it's using the in-kernel radeon instead). as this is my first time trying an alternative kernel, I am out of my depth for this, and there's not a lot of information on Google. I had to piece together information to even get the zen kernel to boot

I would like to not rely on dkms for the video drivers, but I'm not sure how to do that

Last edited by HiImTye (2017-07-09 23:53:02)

loqs · 2017-07-10 00:03:55

Under linux-zen this should find the amdgpu module usr/lib/modules/4.11.8-1-zen/kernel/drivers/gpu/drm/amd/amdgpu/amdgpu.ko.gz

$ modinfo amdgpu

Edit:
The nvidia kernel module is not licensed under the GPL so is distributed separately in kernel specific versions (the nvidia and nvidia-lts package) and a DKMS which should be kernel version agnostic.
All drivers after compilation will be kernel version specific, DKMS builds a version specific module module for each installed kernel with matching headers on boot/install.

Last edited by loqs (2017-07-10 00:27:35)

HiImTye · 2017-08-04 07:49:48

it turns out I had nomodeset enabled, d'oh. rebooting now to see if it fixes it

edit: I also had to blacklist radeon because it super wanted to load.
interestingly, checking journalctl for amdgpu after checking it for radeon the previous times, I noticed this discrepency:

Aug 04 01:13:24 TTop kernel: [drm] radeon: 512M of VRAM memory ready                                                                                           
Aug 04 01:13:24 TTop kernel: [drm] radeon: 2048M of GTT memory ready.

Aug 04 01:15:45 TTop kernel: [drm] amdgpu: 512M of VRAM memory ready           
Aug 04 01:15:45 TTop kernel: [drm] amdgpu: 1024M of GTT memory ready.

any idea why radeon has more available GTT memory than amdgpu?

Last edited by HiImTye (2017-08-04 08:18:50)

Lone_Wolf · 2017-08-04 11:11:49

I also had to blacklist radeon because it super wanted to load.

For Southern islands and Sea Islands (SI and CIK) cards radeon is still the default.
Apart from blacklisting radeon you can also put admgpu (before radeon if you have both) on modules= line in mkinitcpio.conf.

No idea about the GTT difference, but keep in mind radeon kernel module is mature,amdgpu kernel module is not.

HiImTye · 2017-08-04 19:39:25

I tried putting it in modules, both as "amdgpu radeon" as suggested in the wiki, and finally as "amdgpu" but neither worked until I blacklisted radeon, thus it super wanted to load in my journal, there was a line from amdgpu saying that kms is enabled, but radeon would take over

I'm really not sure what generation this card is. it's a kabini, which isn't listed as any of the ones, I think it's post SI and CIK though, I've never had a clear answer from Google. regardless, amdgpu works just fine on it, much better than the radeon drivers.

hopefully the GTT will sort itself out in the future

Last edited by HiImTye (2017-08-04 19:40:24)

Lone_Wolf · 2017-08-06 11:44:10

Kabini is an APU architecure that can come with several integrated video chipset variants..
Use lspci -nn to find out the pci id of the video card chipset, and use that number to look up the exact type of chipset you have.

HiImTye · 2017-08-06 19:35:09

oh, I used that before, the Radeon HD 8240, but it lies somewhere outside of the Sea Islands, as a mobile computing variant with a kabini chip. the AMD page says that it is a GCN family, but doesn't list the family. I guess it technically is a Sea Islands, as it's an HD 8000 series, but it isn't listed in any device list for the Sea Islands I've been able to find (those start at 8350)

Lone_Wolf · 2017-08-07 13:59:55

Sea Islands / CIK .

It's a bit harder to find and not linked from our wiki.
check https://en.wikipedia.org/wiki/Graphics_ … xt#Chips_2 .

Last edited by Lone_Wolf (2017-08-07 14:00:36)

Arch Linux

#1 2017-07-09 07:23:55

amdgpu and custom kernels

#2 2017-07-09 09:34:05

Re: amdgpu and custom kernels

#3 2017-07-09 11:13:11

Re: amdgpu and custom kernels

#4 2017-07-09 23:52:28

Re: amdgpu and custom kernels

#5 2017-07-10 00:03:55

Re: amdgpu and custom kernels

#6 2017-08-04 07:49:48

Re: amdgpu and custom kernels

#7 2017-08-04 11:11:49

Re: amdgpu and custom kernels

#8 2017-08-04 19:39:25

Re: amdgpu and custom kernels

#9 2017-08-06 11:44:10

Re: amdgpu and custom kernels

#10 2017-08-06 19:35:09

Re: amdgpu and custom kernels

#11 2017-08-07 13:59:55

Re: amdgpu and custom kernels

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