RX 7900XT 4k 120hz Adapter
Hi, I'm trying to get 4k 120hz vrr HDR on my 7900xt with bazzite and LG C3 TV. I know AMD on Linux doesn't support HDMI 2.1 so I ordered this cable: https://a.co/d/2EhB0eG. Unfortunately this cable in particular seems to have an issue with 120 hz as setting it to that doesn't give a signal. Is there any other cable people are using on AMD to get 4K 120hz?
12 Replies
I updated the firmware and it works but they disabled VRR. I take it there are no cables that support VRR out there
there are, but it largely depends on two things:
the type of display you have and the type of VRR you want to use, and the type of dongle you use
- HDMI VRR =/= FreeSync
- the dongle you want needs to be advertised to support VRR/FreeSync
I think the LG C3 does support FreeSync
Take a read through this: https://gitlab.freedesktop.org/drm/amd/-/issues/1417
some people on there have been sharing their experiences with different dongles. I myself use this one (recommended in that same thread), however my Sony HDTV only supports HDMI VRR, and not the open source FreeSync 😦 https://www.amazon.com/dp/B08XFSLWQF?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1
GitLab
4k@120hz unavailable via HDMI 2.1 (#1417) · Issues · drm / amd · Gi...
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I’m getting 4k@120hz FreeSync on 7900xtx/OLED65B2PJA via Gamescope. Not all HDMI ports on my model support 120hz so you may want to check.
TIL lossy compression is likely responsible for my refresh rate. That said, I didn’t even notice. HDR colors don’t look as good as windows but I had originally just assumed that was a poor HDR implementation.
do you use a display port dongle? HDMI connection at 4K@120hz can work but its in 4:2:2, with the displayport dongle you can achieve 4:4:4 4K@120hz
Just HDMI. I’m pretty sure you’re right. Is there a way to check the colorspace that’s been output in Linux? My TV doesn’t seem to have an option to show it so I can’t validate.
there was a website i use, but it looks like its down at the time of writing this: http://www.lagom.nl/lcd-test/gradient.php
the other way i check is if i have crushing blacks or black banding in games, but you need to have a trained eye for that, might not be obvious
i am not aware of any way to output this information from the terminal
Thanks I’ll give that a go when it’s back online.
The TV has a setting called FreeSync premium so I should be good with open source implementation.
Also, hah, I'm the bottom post in the gitlab issue
I'll try the linked adapter, reason why I didn't is because I think it uses the same chip as the one I ordered?
I suppose it doesn't hurt to try, the direct DP to HDMI cable has been all sorts of weird
On the stock from where I couldn't get any picture from it at 120hz at any resolution
On the latest firmware 120hz works but they disabled vrr
And on any modded firmware I get the original behavior, but if I try it on a different display it works but the entire screen goes black whenever the screen updates
I deserve that reaction
haha i think half the discord server has commented on it
i recommend amazon in case any dongle doesn’t work you won’t lose money
I'm hoping my cable in particular is defective
Spent a lot of time testing it last night
In case it’s of any help I bought this after reading this thread and seem to be getting full RGB 10bit out 4k@120hz with VRR. No issues at all so far. https://amzn.asia/d/6uWbLrO
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