Re: [REGRESSION] suspend to ram fails in 6.1 due to tpm errors

[Jason A. Donenfeld]

Hi Vlastimil,

Thanks for CC'ing me.

On Mon, Nov 28, 2022 at 09:15:33AM +0100, Vlastimil Babka wrote:
> Dominik on IRC pointed me to commit b006c439d58d ("hwrng: core - start hwrng
> kthread also for untrusted sources"), which could make sense if the TPM was not
> used at all before and now it's used for randomness. But then it probably "just"
> uncovered a pre-existing issue? Maybe there's a race with getting the randomness
> and suspend? Could it be exactly what this patch is attempting to fix?
> https://lore.kernel.org/all/20221103145450.1409273-2-jsd@xxxxxxxxxxxx/

The commit you referenced just turns on some functionality that most
people previously didn't have (but maybe could have, manually). So this
is a case of a new commit unearthing a bug in some old code. We had
something similar happen with a raspi driver and fixed the bug there.
>From the looks of the lore link you provided, it sounds like the same
thing has happened already there to tpm? That this is already fixed by
that commit? I think if you have a system that's readily exhibiting the
issue, the best thing to do would be to try that series, and report
back, maybe even providing your `Tested-by:` line if it works.

I'll play around and see if I can repro too. Looks like you have a T460?
I don't have exactly that but maybe something close enough.

Jason