amdgpu does not support 3840x2160 at 30Hz on kaveri apu

[Davide Corrado]

SOLVED

I opened a ticket here:

https://gitlab.freedesktop.org/drm/amd/-/issues/1425

and they suggested, at the end, the same hint (amdgpu.dc=1).

... which, I was sure, I already tried with no results. Maybe I just
misspelled it, and it didn't work.

It's working now, thank you so much for your help.





On Mon, Jan 4, 2021 at 3:01 PM Deucher, Alexander <Alexander.Deucher at amd.com>
wrote:

> [AMD Official Use Only - Internal Distribution Only]
>
> You might try enabling DC (the newer modesetting infrastructure).  Append
> amdgpu.dc=1 to the kernel command line in grub.
>
> Alex
>
> ------------------------------
> *From:* Davide Corrado <davide at davidecorrado.eu>
> *Sent:* Saturday, January 2, 2021 1:50 PM
> *To:* Deucher, Alexander <Alexander.Deucher at amd.com>
> *Cc:* Koenig, Christian <Christian.Koenig at amd.com>; airlied at linux.ie <
> airlied at linux.ie>; daniel at ffwll.ch <daniel at ffwll.ch>;
> amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>;
> dri-devel at lists.freedesktop.org <dri-devel at lists.freedesktop.org>;
> linux-kernel at vger.kernel.org <linux-kernel at vger.kernel.org>
> *Subject:* amdgpu does not support 3840x2160 at 30Hz on kaveri apu
>
> hello, I'd like to report this issue that I am having since I updated my
> display (samsung U28E590). The amdgpu does not support the native
> resolution of my new monitor, which is 3840x2160*.* Using a HDMI or DVI
> connection (I tried both, same results), the maximum supported refresh is
> 30Hz, so I'm stuck with that (don't have a displayport). The radeon module
> works fine, I'm having this issue just when I use amdgpu (which I'd like
> to, because performance is better).
>
> Some info of my hardware:
>
> cpu: AMD A10-7870K Radeon R7, 12 Compute Cores 4C+8G
> kernel version (I tried different ones and different linux distros, same
> results!): 5.9.16-200.fc33.x86_64 #1 SMP Mon Dec 21 14:08:22 UTC 2020
> x86_64 x86_64 x86_64 GNU/Linux
> Monitor: Samsung U28E590.
>
> description:
> If I boot the system using amdgpu and no video mode selection, the system
> boots but I don't get a screen during boot and in wayland. I can connect
> using ssh, so the system is running fine, just no display; If I force a
> full HD resolution with "video:" in the kernel line, I can see the boot
> process but the screen disappears when wayland starts (because the default
> resolution is 3840x2160 at 30Hz). Using a full HD monitor results in no
> issues, so it must be related to this very 4k resolution.
>
> As I have already stated, radeon module works with the same
> software/hardware configuration.
> thanks you so much for your time :-)
>
> --
> Davide Corrado
> UNIX Team Leader
>
> Via Abramo Lincoln, 25
> 20129 Milano
>
> Tel +39 3474259950
>


-- 
Davide Corrado
UNIX Team Leader

Via Abramo Lincoln, 25
20129 Milano

Tel +39 3474259950
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