Hi Ganapathi,

> OK; Thanks for this; I read it as 'these two issues have different root
> causes';

Not sure if that's the case since we enable link power saving after
every suspend again.

> it is enabled(above output of lspci -vvv); but is there a seperate check to
> know if it could be *entered*;

I don't think there is, maybe there are unofficial debugging tools by
Intel or related manufacturers to read statistics about those states
from the chipset.

> cat: /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us: No
> such file or directory

Sounds like the processor used in the Pro 4 isn't new enough, from the
cpu residency it sounds like S0Ix is working. You can read more about
those states here: https://01.org/blogs/qwang59/2018/how-achieve-s0ix-
states-linux


Also I figured out what the fix for the "Firmware wakeup failed" errors I wrote 
about was: Sleeping for about a second before writing to the PCI power state 
register, so not really a fix, just a workaround...

If you fail to reproduce the issue on the Pro 4 maybe you can get a Pro
2017 and try it on that?

Thanks,
Jonas

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Title:
  Wifi does down "crash" in Surface Pro 4

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