Radeon HD 4650 (AGP) Xorg failure

skiwarz1 · 03-24-2022, 08:06 PM

Hello,
I just installed Slackware 15.0 on a piece of older hardware, a Radeon HD 4650 (AGP interface) paired with a 32-bit Athlon XP 3200+ cpu. I'm able to boot into Slackware, however when I run "startx", X fails to start. The screen pauses for a few seconds, then I see "giving up" and "server error". My /var/log/Xorg.0.log is here: https://pastebin.com/raw/NKPTQdyZ
I'm using the radeon graphics driver, and I've tried a few different Xorg.conf configurations (to include none at all), all giving me the same result. That line about "illegal instruction" leads me to believe there's a problem with the graphics driver itself.
I tried a live OpenSUSE disc and was able to get into X (it also used the radeon driver) without issue, so I know the hardware is good.
Any thoughts?

mrmazda · 03-26-2022, 03:34 PM

Radeon is the only correct kernel device driver, but there are two options for display driver. Try uninstalling xf86-video-ati. The default modesetting DIX display driver that should automatically be used in its place works well automagically with all my old Radeon cards, including HD3470 and HD5450. e.g.

Code:

# inxi -GSI
System:
  Host: big31 Kernel: 5.16.8-1-default arch: x86_64 bits: 64 Desktop: KDE
    v: 3.5.10 Distro: openSUSE Tumbleweed 20220213
Graphics:
  Device-1: AMD RV620 PRO [Radeon HD 3470] driver: radeon v: kernel
  Display: x11 server: X.Org v: 1.21.1.3 driver: X: loaded: modesetting
    unloaded: fbdev,vesa gpu: radeon resolution: 1: 2560x1440~60Hz
    2: 1680x1050~60Hz
  OpenGL: renderer: AMD RV620 (DRM 2.50.0 / 5.16.8-1-default LLVM 13.0.1)
    v: 3.3 Mesa 21.3.6
Info:
  Processes: 154 Uptime: 0h 8m Memory: 3.82 GiB used: 544.1 MiB (13.9%)
  Shell: Bash inxi: 3.3.14

/usr/lib/dri/r600_dri.so from the backtrace comes from Mesa, so I'd probably focus on it if the display driver switch doesn't help.

Petri Kaukasoina · 03-26-2022, 04:24 PM

Quote:

Originally Posted by skiwarz1

32-bit Athlon XP 3200+ cpu.
"illegal instruction"

I may be wrong but I think llvm may insert opcodes that your athlon does not support, and mesa is built with llvm. The mesa package has i586 in its name but it may still contain instructions like CMOV.

LuckyCyborg · 03-26-2022, 04:55 PM

Quote:

Originally Posted by skiwarz1

Hello,
I just installed Slackware 15.0 on a piece of older hardware, a Radeon HD 4650 (AGP interface) paired with a 32-bit Athlon XP 3200+ cpu. I'm able to boot into Slackware, however when I run "startx", X fails to start. The screen pauses for a few seconds, then I see "giving up" and "server error". My /var/log/Xorg.0.log is here: https://pastebin.com/raw/NKPTQdyZ
I'm using the radeon graphics driver, and I've tried a few different Xorg.conf configurations (to include none at all), all giving me the same result. That line about "illegal instruction" leads me to believe there's a problem with the graphics driver itself.
I tried a live OpenSUSE disc and was able to get into X (it also used the radeon driver) without issue, so I know the hardware is good.
Any thoughts?

Looking at your /var/log/Xorg.0.log , I think that at least the Mesa package is compiled with an processor instruction set which is not supported by your CPU. This is the meaning of "illegal instruction"

This also means: very bad news.

It's not about the graphics driver, but about that Slackware 15.0 contains an unknown number of packages which cannot be properly used with your particular CPU.

You may try to build Mesa package locally, but honestly I doubt that's the single one which is affected.

LuckyCyborg · 03-26-2022, 05:01 PM

Quote:

Originally Posted by Petri Kaukasoina

I may be wrong but I think llvm may insert opcodes that your athlon does not support, and mesa is built with llvm. The mesa package has i586 in its name but it may still contain instructions like CMOV.

The AMD's Barton based CPUs like the OP's one has support for CMOV, it's not that old to be an i586.

My bet is on the lack of support for SSE2 instructions, which are heavy used by the software with graphics or media interests.

https://www.cpu-world.com/CPUs/K7/AM...3200DKV4E.html

mrmazda · 03-26-2022, 05:44 PM

Athlon XP didn't register in my brain when I first responded. I took my last Athlon XP out of service in 2020 because I had no interest in trying to work around its lack of SSE2 instructions. There's a current Mageia mailing list thread about possibly redefining its 32-bit support to require SSE2: https://ml.mageia.org/l/arc/dev/2022-03/msg00251.html

skiwarz1 · 03-26-2022, 08:06 PM

So, I went back and installed Slackware 14.2, and X worked fine (albeit a bit laggy).
Since then, I moved back to gentoo, and I started to notice more issues, namely with missing SSE2 support (rust, firefox, librsvg, gtk+, etc. all require it). So I think that's the end of that. If I'm going to have to compile software myself, I'd rather have portage do it for everything, rather than manually compile just a handful of packages. Makes things easier.

Thanks for the advice, everyone.