Linux Desktop, How good is Vega / Polaris

[lichtenstein]

All hey,
I'm planning on building a new machine (ryzen & vega/polaris) for running Xubuntu (dev stuff mostly, and some gaming too). Atm I'm on a broadwell nuc and I've been spoiled by the good quality of Intel's drivers - I've no issues whatsoever on my Xorg/Xfce desktop, it's very snappy, no visual glitches (as I have with nvidia on my laptop) and tear-free too.

Can I expect similar quality and 2d speed from the current state of the open source AMD drivers? From all the tests that Michael has been doing (you ROCK!) I gather that 3d is perfectly usable but what's your experience in your daily desktop use (vega 56)? Any visual issues? How's the video acceleration, do you use vaapi or vdpau (vaapi works nicely with intel)? I run 18.04 with the hwe kernel so that should get to 4.18 soon (and if it doesn't I don't mind updating to 18.10). Mesa is whatever comes with ubuntu.

I'd prefer vega, since it's the newer arch etc., would there be anything that speaks against it? Again, I mean regular daily desktop usage, 3d gaming is secondary.

[lichtenstein]

Thanks for the response, I don't have the machine yet. I want to avoid Intel in my next build but, as I said, their integrated GPU works very well in linux.

What is your experience with AMD gpus on the desktop? That's the info that I'm after at this point, so I can make the decision to go with them instead of with an overpriced Intel cpu/gpu. How's the desktop in 2d, stuff like text, moving windows around? Any visual glitches? Speed? Does tear-free work 100% (because on my laptop with an older nvidia and the closed source drivers, tear-free works but not in full-screen vids and I have some visual issues now and then, like lines appearing where they don't belong and such)?

[gradinaruvasile]

Thanks for the response, I don't have the machine yet. I want to avoid Intel in my next build but, as I said, their integrated GPU works very well in linux.

What is your experience with AMD gpus on the desktop? That's the info that I'm after at this point, so I can make the decision to go with them instead of with an overpriced Intel cpu/gpu. How's the desktop in 2d, stuff like text, moving windows around? Any visual glitches? Speed? Does tear-free work 100% (because on my laptop with an older nvidia and the closed source drivers, tear-free works but not in full-screen vids and I have some visual issues now and then, like lines appearing where they don't belong and such)?

On the APUs (2200G and suppose 2400G too) it works really well with Debian Testingm kernel 4.18/4.19 (both the one from the experimental repos (4.18) and self-compiled from mainline (4.19)), Mesa 18.2/19.0 (18.2 from the experimental repos, 19 built from git).

Note that i use MATE desktop with no compositing, hardware is Gigabyte GA-AB350M-HD3 mobo, 2x8GB 2400MHz RAM, R3 2200G APU (Vega 8 IGP), 2x 19" 1440x900 displays, connected via HDMI and DVI.
Currently i have kernel 4.19.1 from mainline git, mesa 19 built from git. My computer runs 24/7, and has a libvirt/KVM virtual machine running permanently.

What works:
- Playback is tear free
- Moving windows is tear free
- Steam games have all VSync forced and do not tear
- Hardware decoding works, it can decode up to 4K@60Hz h264/h265/VP9 (i use smplayer+mpv or just mpv). Decoding uses VDPAU and VAAPI, the latter having most features (VP9 is only vaapi), but in the same time some h264 videos only decode via hw on VDPAU.
- Hardware encoding works (has some limitations like no b-frames support) for h264 and h265 - i use it via ffmpeg to transcode videos from our phones, they are unnecessarily high bitrate and size.

What does not (note that this list may be inaccurate as in some issues might have been corrected but i didn't test them):

- System lock up after a time if i don't add "rcu_nocbs=0-3" to the kernel command line. This issue is still happens.
- X server lock up and failed gpu resets if i concurrently use the hardware decoding+encoding. The system is responsive otherwise (as in programs that do not depend on X run fine, ssh works) but the GUI cannot be made to work without reboot (manually triggered gpu resets failed, couldn't unload amdgpu). Now i am not sure this still happens, i formed my reflex to avoid this case.

- System locked up if DPMS was activated with both monitors active. I worked this around by disabling DPMS from the screensaver and running a script at login time that checks every 2 minutes if the screensaver is active and if it is, disables one monitor via xrandr then activates DPMS. Now i don't really know if this is still the case, last i checked it was a few kernel versions ago.
- At reboot, the system sometimes hangs when the amdgpu module is loaded with totally blank screen. This i didn't see since quite some time but i cannot say if it was eliminated 100% because i only reboot my computer on kernel changes.

Weird stuff:
The motherboard's monitoring chip (some IT87 variant) is supported sort-of by default (no fan RPM and probably somewhat incorrect temperatures). But if i use the "it87.force_id=0x8728" kernel command line option, it will create a second entry in the sensors list (it8728-isa-0a40 vs the already present it8728-isa-0a60) which seems to report correct data (ones that closely resemble the BIOS reports, both FAN speeds).

[lichtenstein]

Cool stuff, thanks for all your advice (what I'm hearing is: good desktop can be had with AMD these days, great, I don't mind tweaking)! At first I'll see how I'll go with the most current distro I can get, whenever I pull the trigger on ordering all the parts that is. I haven't compiled kernels myself since my olden Gentoo/Athlon64 days over 14y ago (me to wife "honey, look at how fast this things compiles!", wife to me "oh, you're doing the matrix again")... Compiling a kernel on a 2700x will be fun though .

And how is the fan control? Does it all work automatically e.g. fans off on 2d desktop, then they turn on and gradually go up during a 3d game? I appreciate a quiet system (while I code).

[gradinaruvasile]

And how is the fan control? Does it all work automatically e.g. fans off on 2d desktop, then they turn on and gradually go up during a 3d game? I appreciate a quiet system (while I code).

Depends what fan are you referring to. I have an APU so no dedicated GPU, can't say about that.
The CPU fan though is dynamically controlled by default.

[clapbr]

I you have problems, make a good bug report. AMD will fix stability problems in two weeks. Vega have been so long in the market that it should be stable.

not even close to true, they indeed constantly work on the drivers but I have a few critical problems that have been reported for months or even years by me and others and devs don't seem to care. Most of them have an almost auto-response from Danzer or Deucher asking dmesg/xorg logs then when people provides them they usually ignore it.

https://bugs.freedesktop.org/buglist...81&product=DRI

also the lack of proper active moderation makes the experience suck for both users and devs, too many duplicates that never get merged for instance.

[lichtenstein]

Depends what fan are you referring to

I actually meant the fan(s) of a dedicated AMD GPU such as polaris or vega.

I still haven't decided whether I will go for something (currently/finally) cheap like the rx570/580 or go all in and splurge for a vega (whose price has been going doing steadily too). A 580 won't be (always) be enough for my 1440p monitor (to get consistent 60+ fps in current games in its native resolution).

[lichtenstein]

Then you can use vega money to a fast and large pci-e ssd drive and to a fast CPU.

I've a Samsung sata 850 pro which I'll transplant from my current setup. It's not a super duper nvmi drive but in real world scenarios there isn't much of a diff anyway (unless I go with 3d xpoint but those are too expensive atm). I've already decided to go with the 2700x.

What I like about vega is that it's kind of a wild card arch still, as in, they're still adding optimizations in the drivers that make it faster (with polaris I think they've already reached its potential). This is just a feeling that I get based on reviews and benchmarks all over the net (especially here). Then again, I'd pay 2x for about 40%+ performance (plus a beefier PSU) and the miser in me strongly opposes this "most bang for the buck" discrepancy. I'll see if the rx 590 intro that we expect next week will change that (might drop the prices for the 580/570 even further).

[lichtenstein]

Disable cpu freq and fan control in the kernel configuration

Not sure what you mean, are you saying that I should switch off these features in the kernel compilation config or that I should switch them off in grub using some params I don't know about? How would the mobo bios affect the GPU fan speed? Afaik, you can control the cpu & other (case) fans but the GPU is a separate thing.

[lichtenstein]

My ASUS Radeon RX 570 4GB Expedition OC was on sale two weeks ago. I got it with 209 euros. Now it is 259 euros in the same web-shop.

It's cheaper here: 4GB 570s cost around 150-170 (based on geizhals.de).

I can get the 580 nitro+ for around 210 eur. The cheapest vega 56 is 399 (they ran the sapphire one for 350 a few days ago).