On Wed, Nov 22, 2017 at 3:06 AM, Ilia Mirkin <imir...@alum.mit.edu> wrote: > On Tue, Nov 21, 2017 at 8:29 PM, Andy Ritger <arit...@nvidia.com> wrote: >> Hi Martin, > > Martin should have complete answers, > >> >> I was asked to clarify a few things: >> >> (1) Are all the user reports of loud fans on Fermi-era GPUs? > > Yes. Although I believe some GK208 users are also having trouble, > including yours truly. (It's been quite a while since I've checked > though... my memory is weak in that regard.) >
I think there are some Keplers where we drive the fans too loud? Maybe it got fixed, but I am sure some users complaint about this on Kepler GPUs. >> >> (2) When the VBIOS POSTs the card, it loads initial ucode onto the Falcon >> processor (PMU), which will do basic fan management on its own. We call this >> init ucode "IFR" (Init From ROM). nvidia.ko will restore the IFR ucode when >> unloaded. I assume the loud fan symptom occurs after Nouveau is loaded and >> running, correct? I.e., this is a problem in Nouveau's fan control >> programming, rather than a problem in IFR. > > Correct. > >> >> (3) IFR will run until something else is loaded on the Falcon processor >> (PMU). >> On Fermi, I assume the Nouveau kernel driver is uploading the Nouveau-written >> ucode from here: >> >> drivers/gpu/drm/nouveau/nvkm/subdev/pmu/fuc >> >> correct? I only ask to rule out the possibility that IFR and Nouveau are >> both >> attempting to program fans simultaneously. The symptoms you describe don't >> sound like that, but just double checking... > > Correct. > >> >> (4) Given the PMU ucode debacle, I'm embarrassed to ask, but at least on >> Fermi, >> how much does Nouveau strictly depend on Nouveau's PMU ucode? Would it be an >> option to just let IFR continue to manage fans? > > Reclocking is still on our horizon, which clearly won't happen without > nouveau PMU code loaded. Not sure what it's used for until reclocking > becomes a thing on Fermi. > well I plan to use the PMU for the PMU counters readout code. Not that it matters much on Fermi... >> >> (5) Lastly, I was asked how Nouveau determines what fan speed to (attempt >> to) program. > > I'll let Martin answer this, but as you're probably aware, there's 2 > different ways this can be done - there might be a PWM, we might have > to toggle it manually. Maybe something else still. > > Have a look at drm/nouveau/nvkm/subdev/therm/fan.c and the various > bits it ends up calling (pre-GF119 fermi's end up with the nv50 > fan_set, I believe). > > The bios stuff is parsed in nvkm/subdev/bios/fan.c and therm.c, > although I believe Martin's latest analysis is more advanced than > what's in that code. > > Martin's question was very long, but it boils down to this: > > How do we compute the correct values to write into the e114/e118 pwm > registers based on the VBIOS contents and current state of the board > (like temperature). > > We generally do this right, but appear to get it extra-wrong for certain GPUs. > well short answer is: Nouveau parses the vbios and see what it has to do. Apparently it is wrong in some cases. I don't think there is anything else Nouveau tries to do like having its own curves for calculating fan speeds or so. > Cheers, > > -ilia > _______________________________________________ > Nouveau mailing list > Nouveau@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/nouveau _______________________________________________ Nouveau mailing list Nouveau@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/nouveau
