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drm/nouveau/volt: Make use of cvb coefficients

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I'm quite sure that those coefficients are real close, because while
testing the biggest error compared to nvidia was around -1.5% (biggest
error with right coefficients is 12.5mV / 600mV = 2%).

These coefficients were REed by modifing the voltage map entries and by
calculating the set voltage back until I was able to forecast which voltage
nvidia sets for a given voltage map entry.

With these formulars I am able to precisely predict at which exact
temperature Nvidia down- or upvolts due to a changed therm reading.

That's why I am quite sure these are right, or at least really really
close.

v4: Use better coefficients and speedo.
v5: Add error message when speedo is missing.

Signed-off-by: Karol Herbst <karolherbst@gmail.com>
Reviewed-by: Martin Peres <martin.peres@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This commit is contained in:
Karol Herbst 2016-07-12 21:36:09 +02:00 committed by Ben Skeggs
parent 08de5743db
commit 114653c759
1 changed files with 36 additions and 2 deletions
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38
drivers/gpu/drm/nouveau/nvkm/subdev/volt/base.c
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@ -110,13 +110,47 @@ nvkm_volt_map(struct nvkm_volt *volt, u8 id, u8 temp)
vmap = nvbios_vmap_entry_parse(bios, id, &ver, &len, &info);
if (vmap) {
s64 result;
if (volt->speedo < 0)
return volt->speedo;
if (ver == 0x10 || (ver == 0x20 && info.mode == 0)) {
result = (s64)info.arg[0] / 10;
result += ((s64)info.arg[1] * volt->speedo) / 10;
result += ((s64)info.arg[2] * volt->speedo * volt->speedo) / 100000;
} else if (ver == 0x20) {
switch (info.mode) {
/* 0x0 handled above! */
case 0x1:
result = ((s64)info.arg[0] * 15625) >> 18;
result += ((s64)info.arg[1] * volt->speedo * 15625) >> 18;
result += ((s64)info.arg[2] * temp * 15625) >> 10;
result += ((s64)info.arg[3] * volt->speedo * temp * 15625) >> 18;
result += ((s64)info.arg[4] * volt->speedo * volt->speedo * 15625) >> 30;
result += ((s64)info.arg[5] * temp * temp * 15625) >> 18;
break;
case 0x3:
result = (info.min + info.max) / 2;
break;
case 0x2:
default:
result = info.min;
break;
}
} else {
return -ENODEV;
}
result = min(max(result, (s64)info.min), (s64)info.max);
if (info.link != 0xff) {
int ret = nvkm_volt_map(volt, info.link, temp);
if (ret < 0)
return ret;
info.min += ret;
result += ret;
}
return info.min;
return result;
}
return id ? id * 10000 : -ENODEV;