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@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@davidecorrado.eu *Sent:* Saturday, January 2, 2021 1:50 PM *To:* Deucher, Alexander Alexander.Deucher@amd.com *Cc:* Koenig, Christian Christian.Koenig@amd.com; airlied@linux.ie < airlied@linux.ie>; daniel@ffwll.ch daniel@ffwll.ch; amd-gfx@lists.freedesktop.org amd-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org linux-kernel@vger.kernel.org *Subject:* amdgpu does not support 3840x2160@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@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 :-)
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