let me guess, you're adding 0x8D 0x00 0xXX 0x00 to the VoltageObjectInfo init regulator section. What you might not know is that that section is missing on MANY GPUs. What you probably didn't know is that even if it is there, that will only work for MOST GPUs - that is, the ones that have IR3567B-compatible VRM controllers.
would a solution be for him to search for "01 07 0C 00" in the BIOS ROM before applying his "low wattage mode" ?
(and is there even a tool to read this in Linux?)
Well, I wrote my own toolset - so I don't bother with the VBIOS for voltage anymore. But no, that's not a solution. First - those bytes might show up randomly, say, in a command table. If you're going to try and parse the VBIOS, do it properly.
Proper parser of atombios is a nasty thing to write.
On the other hand it is a very nice thing to have.
For example you can discover scheme to downvolt cards with NCP81022 just by parsing a lot of bioses and checking if vendors do something with it.
Or you can make universal bios editor which already supports unreleased Vega.
Second, he should first check VoltageObjectInfo for a voltage object of type 3 (init regulator), and go from there. But there's still a problem - he doesn't know for sure what VRM controller it is.
Other things should be checked too.
And I think in current generation of cards IR3567B vs NCP81022 vs none can be distinguished in bios.
