Steam On Linux Usage Receded Slightly In September

[cj.wijtmans]

Just an FYI, I dealt with this exact problem (Using an LG C1 as a monitor), and even though it can do 4k at 120 Hz in Linux on an AMD GPU, it defaults to ycbcr420. This makes the colors (especially the reds) look like crap. My fix was to do an active HDMI 2.1 to Display 1.4 converter and use that. VRR doesn't work unfortunately, but it defaults to RGB 8b.

As far as I can tell AMD hardcodes the default color space to YCBCR for HDMI and RGB for Display Port. Nvidia lets you change between them. Not sure why they decided to do this, but I've read "wish list" items, but never seen any commits to the drivers that would let you change it. Currently the only way to change is to modify your device ID for your monitor but that only works if your monitor isn't too new. As the decoding is hit and miss for the newer displays (like my C1).

I was able to switch to 10bit by doing ybcr422, it automatically switched to 10bit. I use DP 1.4 cable. It does look very different colour wise but 422 better than 420.

[clockwork]

I am talking about 2x 1440p 144hz HDR10 screens on an AMD 6600XT. 10bit will not turn on anymore and is so longer supported by AMD drivers.
Well nevermind i just noticed HDR10 defines 4:2:0 and not 4:4:4. 🤦🏼♂️ But it should work with 4:4:4 1440p yet is not supported.

Just an FYI, I dealt with this exact problem (Using an LG C1 as a monitor), and even though it can do 4k at 120 Hz in Linux on an AMD GPU, it defaults to ycbcr420. This makes the colors (especially the reds) look like crap. My fix was to do an active HDMI 2.1 to Display 1.4 converter and use that. VRR doesn't work unfortunately, but it defaults to RGB 8b.

As far as I can tell AMD hardcodes the default color space to YCBCR for HDMI and RGB for Display Port. Nvidia lets you change between them. Not sure why they decided to do this, but I've read "wish list" items, but never seen any commits to the drivers that would let you change it. Currently the only way to change is to modify your device ID for your monitor but that only works if your monitor isn't too new. As the decoding is hit and miss for the newer displays (like my C1).

[clockwork]

For the steady stream of users fleeing both Arch & Manjaro because of guaranteed breakage every fortnite, having five years of stability certainly does...

fortnite doesn't run on linux....






(obviously just being funny)

[cj.wijtmans]

With 8bit I'm pretty darned sure that 4k 120Hz 4:4:4 is specifically what DisplayPort 1.3 is spec'd for; the following may be useful in that regard:
https://linustechtips.com/topic/7292...s-adapters-v2/

But with 10bit I do believe that one needs DSC (display stream compression) in order to achieve 4k 120Hz 4:4:4 with DisplayPort at this time; if your GPU and monitor don't both support DSC than you're stuck with lower refresh rates (I think it's somewhere around 100Hz?) unless you set bit depth to 8bit.

...unless your issue is the 4:4:4 chroma thing I spoke of on the previous page.

I am talking about 2x 1440p 144hz HDR10 screens on an AMD 6600XT. 10bit will not turn on anymore and is so longer supported by AMD drivers.
Well nevermind i just noticed HDR10 defines 4:2:0 and not 4:4:4. 🤦🏼♂️ But it should work with 4:4:4 1440p yet is not supported.

[jaxa]

Allot of trouble, keep in mind HDMI2.1 offers 48Gbps while DP1.4 is still limited to 24Gbps I think..

DP1.4 is 25.92 Gb/s of 32.4 Gb/s total bandwidth
DP2.0 is 77.37 Gb/s of 80 Gb/s (changed encoding scheme).

https://en.wikipedia.org/wiki/DisplayPort#Specifications

DP2.0 isn't a thing yet, even 40 series don't have it. Only new Intel GPU's and MAYBE AMD 7000 cards... this basically means almost nobody will be able to resolve this issue by themselves anytime soon. We back to waiting on HDMI Forum to stop being pains!

Ryzen 7000 CPUs support HDMI 2.1 and DP 2.0 from the iGPU, but DisplayPort is limited to UHBR 10 (10 Gbps per lane), which would be 38.69 Gb/s (40 Gb/s):

https://cdn.mos.cms.futurecdn.net/4Z58vQfQz2bMeAdDtvgSW8-970-80.jpg.webp

RX 7000 (RDNA3) should support UHBR 20 and the full capability of DisplayPort 2.0:

https://www.tomshardware.com/news/amds-rdna-3-will-support-displayport-20-and-uhbr20

[theriddick]

Well I found out SP196 CHIP will have DP2 to HDMI2.1 support with VRR. But it only JUST got announce so give it a year. Allot of trouble, keep in mind HDMI2.1 offers 48Gbps while DP1.4 is still limited to 24Gbps I think..

DP2.0 isn't a thing yet, even 40 series don't have it. Only new Intel GPU's and MAYBE AMD 7000 cards... this basically means almost nobody will be able to resolve this issue by themselves anytime soon. We back to waiting on HDMI Forum to stop being pains!

Also I'm pretty sure you can't use DSC with HDMI 2.0 and older because DSC relies on the packet-based nature of DisplayPort and/or HDMI 2.1.

You need to deploy driver hacks under Linux to force custom signal switching.
I've been through this already, spent over a week doing in-depth problem solving. Unless someone can setup a camera and show me they found a solution; I won't be subscribing to any more theories... some of us actually want to use their PC's not just spend months problem solving!

[NM64]

Isn't DP2.0 meant to allow VRR? I kind of don't want to loose features, screen probably does have DSC since its a newish higher end one (LG C1).

You mean VRR over active adapters, right? Because even DP1.2a supports VRR and predates VRR over HDMI by several years (in fact, VRR originated on eDP from panel self-refresh).

And yes, the C1 supports DSC, but it's kind of a moot point since the panel is 10bit and maxes out at 4k 120Hz anyway which is enough even for 40Gbps HDMI let alone 48Gbps (though, in theory, DSC could be useful for devices like the PS5 which have a mere 32Gbps HDMI 2.1 output, almost like it's actually internally outputting DisplayPort 1.4...).

Also I'm pretty sure you can't use DSC with HDMI 2.0 and older because DSC relies on the packet-based nature of DisplayPort and/or HDMI 2.1.

[theriddick]

Losing VRR is a given but, as for if they work or not, they definitely work for 4k 120Hz on Windows with the aforementioned caveats. Was this the case for you, i.e. it's just that they don't work on Linux, not that they don't work at all?

I can't remember now if I tested on Windows or not, think I did. Isn't DP2.0 meant to allow VRR? I kind of don't want to loose features, screen probably does have DSC since its a newish higher end one (LG C1).

Either way its such a hassle messing with all the million ways to try and solve it, to only come away empty handed.... I truly hate Linux's crap display handling, its built all around programming and NOT for desktop users expecting advanced functionality..

I remember not that long ago people telling me to shut up about the acquaintances with display management under Linux since i should only be doing productivity/programming stuff anyway and NOT gaming/power-desktop-usage stuff.. (streaming etc).

Anyway improvements are being worked on, at snails pace however...

[NM64]

Those don't work! Already tried a few. They default back to 4k60hz which I do not want. Also you loose VRR...

Losing VRR is a given but, as for if they work or not, they definitely work for 4k 120Hz on Windows with the aforementioned caveats. Was this the case for you, i.e. it's just that they don't work on Linux, not that they don't work at all?

[theriddick]

Nevertheless, have you considered the option of an active DisplayPort 1.4 to HDMI 2.1 adapter?

Those don't work! Already tried a few. They default back to 4k60hz which I do not want. Also you loose VRR... It will only be possible with DP2.0 adapters.. maybe... Time will tell.