*quote from guru3d user "lucky_noob" and unwinder
Doing i2c dump indeed cause black screen crash. But if we scan some specific areas we can get the values:
Scanning GPU VEN_1002&DEV_7300&SUBSYS_0B361002&REV_C8&BUS_3&DEV _0&FN_0...
Scanning I2C bus 0...
Probing device 30...
Invalid device
Scanning I2C bus 1...
Probing device 30...
Invalid device
Scanning I2C bus 2...
Probing device 30...
Invalid device
Scanning I2C bus 3...
Probing device 30...
Invalid device
Scanning I2C bus 4...
Probing device 30...
Invalid device
Scanning I2C bus 5...
Probing device 30...
Invalid device
Scanning I2C bus 6...
Probing device 30...
29 14 1B 0F 16 1E 7C 49 4A 7D 11 66 66 44 FF FF
A2 22 80 10 29 FF 20 00 00 00 00 00 00 00 00 00
00 00 60 60 1C 1E FF 8D 3C 26 A3 31 38 A1 1F 31
38 07 FC 74 6F 05 05 1D 81 A0 60 00 00 66 00 00
A8 90 00 00 00 00 3C 00 14 14 00 40 80 60 60 FF
FF 00 40 88 34 88 44 12 02 02 88 00 20 20 00 3C
3C 03 7D 61 3C 9C 24 88 80 00 00 00 00 FF 06 FF
FF 20 00 00 00 00 00 00 00 00 00 00 15 15 00 00
00 00 3C 00 00 00 00 00 88 88 01 C2 44 00 00 1F
00 05 43 68 28 01 30 70 5E A8 73 A6 02 3C 1E 1F
00 00 00 00 00 00 01 01 08 55 A0 8F CF 00 00 05
04 00 00 00 00 FF 23 C3 00 00 7A 6E 9E 15 3C 00
00 00 00 77 13 00 00 00 00 00 00 03 00 44 00 00
00 00 AD 50 0C 00 10 00 3F 00 00 00 23 C0 F0 1E
00 1F 00 10 01 03 01 88 00 00 00 00 3C 00 00 00
00 00 00 00 00 33 00 00 00 00 00 00 00 00 00 00
Scanning I2C bus 7...
Probing device 30...
29 14 1B 0F 16 1E 7C 49 4A 7D 11 66 66 44 FF FF
A2 22 80 10 29 FF 20 00 00 00 00 00 00 00 00 00
00 00 60 60 1C 1E FF 8D 00 26 A3 31 38 A1 1F 31
38 07 FC 74 6F 05 05 1D 81 A0 60 00 00 66 3C 00
A8 90 00 00 00 00 00 00 14 14 00 40 80 60 60 FF
FF 00 40 88 34 3C 44 12 02 02 88 00 20 20 00 3C
3C 03 7D 61 68 9C 24 88 80 00 00 00 00 FF 06 FF
3C 20 00 00 00 00 00 00 00 00 00 00 15 15 00 00
00 00 00 00 00 00 00 00 88 88 01 3C 44 00 00 1F
00 05 43 68 28 01 F0 70 5E A8 73 A6 02 01 1E 1F
00 00 00 00 00 00 01 01 08 55 A0 8F 3C 00 00 05
06 00 00 00 00 FF 23 C3 00 00 7A 6E A9 15 00 00
00 00 FF 77 13 00 00 00 00 00 00 03 01 3C 00 00
00 00 AD 50 0C 00 10 00 3F 00 00 00 23 C0 F0 00
00 00 00 10 01 03 01 88 00 00 00 00 00 00 3C 00
00 00 00 00 00 33 00 00 00 00 00 00 00 00 00 00
Probing with /ri6, 30, 92 (or ri7,30,92), gives 43 response, so I'm trying to use the third party voltage control method and made msiafterburner.oem2 file consist on these lines:
;OEM
[VEN_1002&DEV_7300&SUBSYS_0B361002&REV_C8]
VDDC_IR3567B_Detection=6:30h
VDDC_IR3567B_Type= 1
VDDC_IR3567B_Output= 0
And the voltage control shows a value that can be controlled up to +100mV *sorry can't post image/link yet*, but every time I alter those voltages, the Card frequencies are sometimes stuck in 300Mhz even with 3D load.
I tried the other way using normal voltage control method, adding this line to the hardware profiles using
[Settings]
VDDC_IR3567B_Detection = 30h
VDDC_IR3567B_Output = 0
But the result is the same, the voltage control shows a slider to +100mV but when you set it, the card stuck to 2D Frequencies.
I'll probably do more test when my preordered card is delivered, the one I'm testing with already returned back to AMD.
*/unwinder
That's both positive and negative info. Positive: device 30h in the dump is IR3567B with no doubts, so driver-level I2C access is indeed working and VRM can be accessed on software level. Negative: such reaction on overvolting (graphics card downclocking) smells by hitting some hardware limit, I'm not too optimistic on improving it.