From 114653c7593a4dd52cc1721b0d325d43b00e2371 Mon Sep 17 00:00:00 2001 From: Karol Herbst Date: Tue, 12 Jul 2016 21:36:09 +0200 Subject: [PATCH] drm/nouveau/volt: Make use of cvb coefficients 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 Reviewed-by: Martin Peres Signed-off-by: Ben Skeggs --- .../gpu/drm/nouveau/nvkm/subdev/volt/base.c | 38 ++++++++++++++++++- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/volt/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/volt/base.c index 771419ff8338..90d234231eed 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/volt/base.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/volt/base.c @@ -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; -- 2.20.1