Re: k10temp: ZEN3 readings are broken
From: Guenter Roeck
Date: Wed Dec 23 2020 - 09:26:54 EST
On 12/23/20 2:41 AM, Jan Engelhardt wrote:
>
> On Tuesday 2020-12-22 04:58, Guenter Roeck wrote:
>> On 12/21/20 5:45 PM, Gabriel C wrote:
>>> Hello Guenter,
>>>
>>> while trying to add ZEN3 support for zenpower out of tree modules, I find out
>>> the in-kernel k10temp driver is broken with ZEN3 ( and partially ZEN2 even ).
>>
>> [...] since I do not have time to actively maintain
>> the driver, since each chip variant seems to use different addresses and scales,
>> and since the information about voltages and currents is unpublished by AMD,
>> I'll remove support for voltage/current readings from the upstream driver.
>
> I support that decision.
>
> /proc/cpuinfo::AMD Ryzen 7 3700X 8-Core Processor, fam 23 model 113 step 0
>
> A synthetic load (perl -e '1 while 1') x 16 shows:
> Adapter: PCI adapter
> Vcore: +1.28 V
> Vsoc: +1.02 V
> Tctl: +94.8°C
> Tdie: +94.8°C
> Tccd1: +94.8°C
> Icore: +76.00 A
> Isoc: +6.75 A
>
> A BOINC workload on average:
> k10temp-pci-00c3
> Adapter: PCI adapter
> Vcore: +1.17 V
> Vsoc: +1.02 V
> Tctl: +94.9°C
> Tdie: +94.9°C
> Tccd1: +95.0°C
> Icore: +88.00 A
> Isoc: +8.00 A
>
> The BOINC workload, when it momentarily spikes:
> Adapter: PCI adapter
> Vcore: +1.32 V
> Vsoc: +1.02 V
> Tctl: +94.1°C
> Tdie: +94.1°C
> Tccd1: +96.0°C
> Icore: +105.00 A
> Isoc: +7.75 A
>
> For a processor sold as a 65 W part, observing reported sensors as
> 88 A x 1.17 V + 8 A x 1.02 V = 111.12 W just can't be. We are off by a
> factor of about 2.
>
Currents were always supposed to be unscaled. So this post is again
proving my point.
Either case, the code removing voltage and current support is now upstream.
Guenter