Fixes for https://github.com/raspberrypi/linux/issues/7301

[by]

These are the two fixes I successfully tested to mitigate #7301

[popcornmix]

Any fixes to code that is unchanged in our downstream (rpi-7.0.y) kernel will need to be submitted upstream.
See here.

[by]

Thanks, and I'm trying to get this done, but it is not trivial for a non-kernel developer, as it appears; have reached out via email to check.

The two regarding RP1 (6b29188 and 0504cd9) are independent of the others, only for Pis with the RP1 and not related to upstream linux, if I'm not mistaken? I should have created two pull requests, my mistake, I'm sorry.

[popcornmix]

Yes, I think the RP1 commits affect downstream code, so belong here.

The PPS commits looked to be editing files we haven't changed downstream, so belong upstream.
We can pick them up once they are accepted upstream, but the (upstream) code devs are in a better position to judge the changes to be correct (and advise if not).

[nbuchwitz]

Thanks, and I'm trying to get this done, but it is not trivial for a non-kernel developer, as it appears; have reached out via email to check.

The two regarding RP1 (6b29188 and 0504cd9) are independent of the others, only for Pis with the RP1 and not related to upstream linux, if I'm not mistaken? I should have created two pull requests, my mistake, I'm sorry.

Regarding the non-rp1 commits:

The pps-gpio threaded IRQ split is clean and nearly ready for upstream as-is. I'd lead the series with that one.

The raw_spinlock conversion needs some rework though. pps_event() calls wake_up_interruptible_all(), kill_fasync(), and the echo callback all under the lock - those can sleep on RT and must not be held under raw_spinlock. You'd need to move those out of the critical section first, then do the conversion. That makes it a 2-3 patch mini-series on its own.

If this is your first touchpoint with the upstream process and you'd like help getting this posted to the mailing list, feel free to reach out - happy to guide you through the process.