Regression: RX 470 fails to boot with amdgpu.dpm=1 on kernel 6.7+

[Alex Deucher]

On Thu, May 22, 2025 at 11:10 AM Durmuş <dozaltay at gmail.com> wrote:
>
> Hello,
>
> I'm experiencing a critical issue on my system with an AMD RX 470 GPU.
> When booting with recent kernel versions (6.7.x or newer), the system
> fails to boot properly unless I explicitly disable Dynamic Power
> Management (DPM) via the `amdgpu.dpm=0` kernel parameter.
>
> When DPM is enabled (`amdgpu.dpm=1` or omitted, since it's the
> default), the system either freezes during early boot or fails to
> initialize the display. However, using the LTS kernel (6.6.x),
> everything works as expected with DPM enabled.

Are you still having an issue with newer kernels?  E.g., 6.14 or 6.15?
 I haven't seen any problems with polaris boards here.  If 6.6.x
works, but 6.7 does not, can you bisect?

Alex

>
> This seems to be a regression introduced in kernel 6.7 or later, and
> it specifically affects older GCN4 (Polaris) GPUs like the RX 470.
> Disabling DPM allows the system to boot, but significantly reduces GPU
> performance.
>
> Things I’ve tried:
> - Confirmed that the latest `linux-firmware` is installed.
> - Verified correct firmware files exist under `/lib/firmware/amdgpu/`.
> - Tested multiple kernels (mainline and LTS).
> - Using Mesa with ACO (Radeon open driver stack).
> - System boots fine with LTS kernel (6.6.x) + DPM enabled.
>
> System info:
> - GPU: AMD RX 470 (GCN 4 / Polaris)
> - Distro: Arch Linux
> - Kernel (working): linux-lts 6.6.x
> - Kernel (broken): 6.7.x and newer (currently tested on 6.14.6)
>
> Thanks in advance,
> Durmus Ozaltay