linux-kernel - Re: [PATCH] x86/thermal: Fix LVT thermal setup for SMI delivery mode

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Message-ID: <e23ae63a-8b5b-f2e7-1037-05808a4d08df@nurealm.net>
Date:   Fri, 28 May 2021 01:05:14 -0600
From:   James Feeney <james@...ealm.net>
To:     Borislav Petkov <bp@...e.de>
Cc:     linux-smp@...r.kernel.org, Jens Axboe <axboe@...nel.dk>,
        lkml <linux-kernel@...r.kernel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        x86-ml <x86@...nel.org>
Subject: Re: [PATCH] x86/thermal: Fix LVT thermal setup for SMI delivery mode

On 5/27/21 4:31 AM, Borislav Petkov wrote:
> it took me a while to find a box like yours to reproduce on. Anyway,
> here's what looks like the final fix, you could give it a run.

Going through the motions, I can confirm "no surprises".  The final patch is working as expected, with both full power-off boots and "warm" reboots.

On 5/27/21 12:09 PM, Srinivas Pandruvada wrote:
> My guess is that system is booting hot sometimes. SMM started fan or
> some cooling and set a temperature threshold. It is waiting for thermal
> interrupt for temperature threshold, which it never got.

I remind, that when the boot would hang at "Trying to unpack rootfs image as initramfs...", then if the machine is let sit in this state, the fan will begin to run full, off and on, suggesting that maybe the processor is still running and running full power.  Something - maybe the management engine? - is still running, and able to cycle  the fan speed, high and low.  There *must*, then, be "high" and "low" temperature thresholds being reached, as the fan speed cycles, and there is *no* continuation of the boot process when either of these thresholds is reached.  So that interpretation - waiting for thermal interrupt - does not seem to address all the circumstances.

James