Hi Cachy-Team,
will you be able to include a working version of the HDMI 2.1 workaround for AMD cards in future CachyOS releases?
Or will this be something we will always have to do ourselves?
you have to wait linux 7.0
There is an AUR package, which however I did not check
linux 7.0-rc1 has been released yesterday. Normally today/tomorrow (although in some cases there can be a few days of delay) you will find it in the rc branch of the cachyos kernel. Try sudo pacman -Syu linux-cachyos-rc linux-cachyos-rc-headers when you see the the 7.0-rc1 version proposed for the install, you are good to go.
For context, HDMI not only does not release open or closed firmware/driver. They do not even release the specs of 2.1 to block chances of backengineering or come with independent drivers. The idea/excuse is that one can use the output at the cable to record high-definition video for pirating. I have no idea how they pulled this. If it works consistently, it is a big deal.
bumping this, I’m a bit confused, is experimental AMD HDMI 2.1 support included in the 7.0 rc?
Thought it was going to stay an out of tree driver?
you can check theses points
I don’t see anything that would indicate a submission by Michał Kopeć who is the author of this. Also, I believe AMD is part of the HDMI forum so that was another reason to keep it out of tree from what I understand of the situation.
Phoronix article
https://www.phoronix.com/news/AMDGPU-HDMI-2.1-FRL
While it’s interesting and the passionate work of open-source developers applauded, it’s likely not to yield any short-term improvement for AMD Radeon Linux users at large. Besides those wanting to roll their own kernel build with these patches, these patches certainly wouldn’t be accepted for upstreaming to the AMDGPU driver given HDMI Forum’s rejection already and needing to clear AMD’s legal review. It may help apply pressure on the HDMI Forum to change course especially if Valve and other stakeholders get involved, but this has been an unfortunate issue going back years already. AMD Linux users are best off just using DisplayPort where possible. Or if the HDMI Forum doesn’t revert their policy, perhaps in some future AMD GPUs we’ll find more of the HDMI display functionality moved into their binary firmware blobs to make it easier on the open-source driver.
I switched my TV computer from Win10 to Cachy this weekend and HDMI connection supported 4K 120hz 10bit HDR and VRR out of the box. So I think it’s already carrying whatever patches are needed for HDMI2.1
I do not have this same experience. I am on latest cachyos kernel, I have tried the rc as well. I’m not sure how you’re getting full HDMI2.1 bandwidth. Are you sure it is HDMI and not Display Port? I am curious what TV you have, are you willing to share?
Yeah, it’s definitely HDMI port going to an LG C3
Very interesting. I have an LGC9 (before they started over with CX, C1, etc…) and I know that 120hz VRR was retrofitted into this model with a software update way back. Full HDMI2.1 bandwidth worked on windows with this TV but I am not able to get it to work now on linux. I may have to look into upgrading.
I have an LG E9 and the refresh rate also only goes to 60 Hz, when connected to HDMI. However, HDR and VRR work. When I connect the TV to display port using an adapter, I can set it to 120 Hz. However, VRR will not function in this configuration because 2019 LG OLED TVs do not support FreeSync, only HDMI VRR, which is not supported by DisplayPort.
So its included now?
bump I’d like to know too!
I can enable 4K@120Hz with VRR and HDR10 but I get color banding. So… does it work or not?
see this 
https://www.phoronix.com/news/AMDGPU-HDMI-2.1-FRL-Patches
no full support HDMI 2.1 , no VRR for instance , it will coming