The OhGodAVBIOS Suite - Edit PowerPlay Tables, Decode Timings, and More!

[AlainC]

so voltage control not possible with linux?

On phoronix they say some improvement are possible with next kernel versions
https://www.phoronix.com/scan.php?page=news_item&px=AMDGPU-Linux-4.17-Round-1

I've recompiled amdgpu module with this kind of change
https://www.phoronix.com/forums/forum/linux-graphics-x-org-drivers/amd-linux/918649-underclocking-undervolting-the-rx-470-with-amdgpu-pro-success
but in fact, I see that the numbers are already changed because of the bios power state, but that it have no effect. I could not continue investigation.

As far as I understand if one understand which memory have to be read/set to control the i2c, and understand the vbios tables (as read by AtomBiosReader), one could do what amdgpu do when interpreting the vbios pseudocode (x86 if I understand well). all normally is in the amdgpu driver, and as I suspect it could even be done with /dev/mem.
best of course would be to use sysfs peudo files calling subroutins in amdgpu, like it is already proposed for pp_*

[VirosaGITS]

Sorry i haven't kept watch on this thread.

We have this currently available as a private tool called OhGodAVolt. This handle communicating with the various VRMs to control it according to specifications.

As someone brought up before, AMD is releasing stuff for Polaris Soon™. Our tool isint limited in this regard, however.

[QuintLeo]

As someone brought up before, AMD is releasing stuff for Polaris Soon™. Our tool isint limited in this regard, however.

Polaris undervolt under AMDGPU is possible NOW (and I think it also can be done for Vega but haven't actually looked at the code for that) - but you have to hack the applicable kernal module and it's an ugly mess - and trying to do it with individual undervolt for each card is going to be a major PITA on the current AMDGPU version.
AMDGPU however does NOT support undervolt OR clock control for R9 series cards (try it, the clocks DO NOT MOVE no matter what settings you use), and STILL offers exactly ZERO support at all for the iGPU on AMD A-series CPUs (even the GCN ones)
OpenCL for SOME APU models under ROCm is supported (works on the 7890k and 7860k, I've not tested on the 5700 as that's pre-GCN, and I don't have any other models to test it on) but forget trying to use APU graphics if you have anything else in the system using AMDGPU.

*SUPPOSEDLY* they are adding undervolt control to "the next version" of AMDGPU - but ghods only know when that will show up, and if it will work with anything OTHER THAN Polaris or Vega.


In my testing, the undervolt DID reduce power consumption some on Polaris cards that are not already BIOS modded, but I don't recommend trying to do so on modded cards due to how the driver code is set up.
The Phoronix "818" figure proved to be rather optimistic across a range of RX 470/480 cards for stability though, I think I ended up at 850 or 860 before I finally got the rig to be stable for more than a couple hours at a time.


Real driver support on a per-card basis would be a LOT better.

[nerdralph]

AMDGPU however does NOT support undervolt OR clock control for R9 series cards (try it, the clocks DO NOT MOVE no matter what settings you use)

It works fine for GCN3 (i.e. Tonga).

Code:

sudo ./ohgodatool -i $r380 --core-state 5 --core-clock 906
sudo ./ohgodatool -i $r380 --core-state 5 --core-vddc-idx 1

It's not quite as good as Polaris, because the AMDGPU driver seems to use fixed voltage tables with Tonga rather than EVV.
You also need to watch out for the ACPI bug that causes powerplay to fail.  It seems BIOS and slot dependent, so you might not encounter it.  I had problems with the the 16x slot on H97 anniversary boards, and after trying a couple different BIOS versions I gave up and just use the 5 1x slots.

[QuintLeo]

Interesting, as the actual "put code in the mclk and sclk" type stuff in sysfs does NOT actually change the clocks when I tried it on my 4 x R9 290 rig or my mixed R9 280x/HD7850/HD7750 rig.

Did you check /sys/kernel/debug/dri/0/amdgpu_pm_info to see if the clocks actually CHANGED? (change the 0 for the specific card being checked of course).


Might also be a "R9 3xx" vs "R9 2xx" difference, or a GCN 3 vs older GCN versions difference, if it DOES actually work - I only have R9 290/280x + HD 7870/7850/7750 cards to test on while GCN 3 wasn't introduced 'till the R9 285 (Tonga) card.

[kiaas]

Interesting, as the actual "put code in the mclk and sclk" type stuff in sysfs does NOT actually change the clocks when I tried it on my 4 x R9 290 rig or my mixed R9 280x/HD7850/HD7750 rig.

Did you check /sys/kernel/debug/dri/0/amdgpu_pm_info to see if the clocks actually CHANGED? (change the 0 for the specific card being checked of course).


Might also be a "R9 3xx" vs "R9 2xx" difference, or a GCN 3 vs older GCN versions difference, if it DOES actually work - I only have R9 290/280x + HD 7870/7850/7750 cards to test on while GCN 3 wasn't introduced 'till the R9 285 (Tonga) card.

an old thread, but a few things for anyone that runs across it that still cares about using old cards: at least GCN 1 and 2 don't work with the amdgpu way of overclocking, AND some of the cards have "quirks" coded into the driver that sets a max speed, so even a vbios mod to, say, take the memory of a 7850 and run it at 1500mhz won't work because it's coded into the driver to not allow it over 1200mhz, Core clock was also maxed out at one point but I think that got lifted on the 7850. It's possible to mod that part of the driver even with the amdgpu-pro one.. once that's edited, you can change clocks and voltages for cards in the vbios. hex editing and VBE7 are the things to do that for pitcairn (7850, 7870, r7 265 r9 270/270x and r7 370.) tahiti (7950, 7970, 7990, 7870 XT, 280, 280X). I'd expect it to work on 7750 and 7770 too, but not 7790, as 7790 is actually GCN 2 like the 290(X) and 390(X) are. Not sure if Hawaii Bios Editor can handle the 7790, but otherwise that's the tool for those. GCN 3 cards, like the R9 285 and 380.. not sure if overclocking works with the amdgpu way, and I'm unsure what vbios editing tools work with them.

edit: as for the 7870 XT, which is different from the 7870, it's got a Tahiti core stripped down to a 256bit bus like Pitcairn but has more compute units and better FP64 performance on those units than Pitcairn has.