Am 08.11.24 um 17:57 schrieb Werner Sembach:
Hi Guenter,
Am 08.11.24 um 17:26 schrieb Guenter Roeck:
On 11/8/24 08:13, Werner Sembach wrote:
Hi,
Am 08.11.24 um 15:30 schrieb Guenter Roeck:
On 11/8/24 04:05, Werner Sembach wrote:
Hi everyone,
I'm currently conceptualizing an upstream implementation for the
fan control on our Sirius 16 Gen 1 & 2 devices which has the
following custom WMI functions (pseudo code):
void SMOD(bool mode): Toggle firmware controlled fans vs manually
(aka via the commands below) controlled fans
bool GMOD(): Get current SMOD setting
int GCNT(): Get number of fans
enum GTYP(int index): Returns "CPU-fan" or "GPU-fan"
void SSPD(int index, int value): Set fan speed target as a
fraction of max speed
int GSPD(int index): Get current fan speed target as a fraction of
max speed
int GRPM(int index): Get current actual fan speed in revolutions
per minute
int GTMP(int index): Get temperature of thing fan with respective
index is pointed at (CPU or GPU die, see GTYP)
However there are some physical limitations that are not in the
firmware and I would like to implement as low as possible in
software, aka the driver, to avoid hardware damage:
1. Valid fan speeds are 0% (fan off) and 25-100%. Values from
1%-24% must not be written.
2. As long as GTMP is > 80°C fan speed must be at least 30%.
We would love to see the same driver enforced restrictions in the
Uniwil driver Armin is working on and the Clevo driver Juno
Computers is working on.
My Idea so far:
1. Round SSPD input: 0-12% -> 0%, 13-25% -> 25%
That is acceptable.
2. Periodically check GTMP (every second should be enough) in
driver and if the temperature is over 80°C set current and
incoming speed commands to at at least 30%.
Is this legitimate with the hwmon design?
No. That would have to utilize the thermal subsystem. hwmon is not
intended to
_control_ the environment, only to monitor it.
Thanks for the hint, I was not aware of the thermal subsystem until
now.
But still wondering, doesn't have the hwmon interface also some
write functionality? Or am I completely mistaken here?
That is to set limits and other chip configuration, not for active
environmental control.
From the thermal subsystem I found my way to this page:
https://www.kernel.org/doc/html/latest/driver-api/thermal/nouveau_thermal.html
-> "1: The fan can be driven in manual (use pwm1 to change the speed);"
So it seems like the thermal subsystem is exposing a pwm hwmon
attribute itself which can be used for manual control.
I don't think so, the hwmon interface is exposed by the nouveau driver itself, see drivers/gpu/drm/nouveau/nouveau_hwmon.c for details.
Thanks,
Armin Wolf
Second question: Is there a good way to implement a userspace
controlled switch between auto and manual mode?
Only if that is a direction to the chip to switch between modes.
Yes, via WMI you can set the mode to "manual", then you can use the
wmi to set the fan speed to whatever speed you like. When it is set
to auto, the EC itself applies an internal fixed fan curve.
The standard attribute for that would be pwmX_enable (since fans are
usually controlled through pwm).
Thanks for the input so far. I have to look deeper into the thermal
subsystem.
Regards,
Werner
Guenter
Thanks,
Guenter
Kind regards,
Werner
PS.: By missclick I accidentally sent an empty email before. just
ignore it.
