> -----Original Message-----
> From: Andrew Lunn <and...@lunn.ch>
> Sent: Sunday, June 23, 2019 7:26 PM
> To: Vadim Pasternak <vad...@mellanox.com>
> Cc: Ido Schimmel <ido...@idosch.org>; netdev@vger.kernel.org;
> da...@davemloft.net; Jiri Pirko <j...@mellanox.com>; mlxsw
> <ml...@mellanox.com>; Ido Schimmel <ido...@mellanox.com>
> Subject: Re: [PATCH net-next 3/3] mlxsw: core: Add support for negative
> temperature readout
>
> > > Why the > 0?
> >
> > We don't consider negative temperature for thermal control.
>
> Is this because the thermal control is also broken and does not support
> negative
> values? This is just a workaround papering over the cracks?
We just have system hardware requirements for minimal speed for system
PWM. It could not be less than 20%.
So for temperature ~40C or below it PWM will set to this speed.
>
> I've worked on some systems where the thermal subsystem has controller a
> heater. Mostly industrial systems, extended temperature range, and you have to
> make sure the hardware is kept above -25C, otherwise the DRAM timing goes to
> pot and the system crashed and froze.
Interesting input. I didn't know about such feature.
We don't have heaters within our systems.
Maybe we should think about it for the next generatin systems.
>
> Andrew
