Wake from sleep kinda broken-ish? (ThinkPad Carbon X1 6th gen)

[Eirik Øverby]

On Wednesday, September 16, 2020 9:05:43 AM CEST Warner Losh wrote:
> I too can report this for my Lenovo Yoga running code as of September 13,
> but with manu's latest drm...  It used to work fine, but my last build on
> the system was from May. Most likely a new panic in that code path, but
> I've not chased down further...

So I got a gen8 to play with, and the list of grievances is long - but I have 
one observation that may be of interest:
The gen8 would be usable (at least seemingly so) with a 13-kernel from lat 
2019 or very early 2020. Then around the end of January - I've bisected it 
down to around Jan 24, give or take, it would start wedging _hard_ after a 
minute or two of heavy load (compiling, cat /dev/random, that sort of thing). 
It was a problem prior to that too but it was _much_ harder to trigger, at 
least based on my tests this weekend.

The "solution" is to add
  hint.hwpstate_intel.0.disabled="1"
to /boot/loader.conf. This obviously has disastrous impact on battery life. 
The emt module takes over, so power management is a lot more rudimentary 
(powerd now does nearly nothing, while powerd++ kills interactivity). Battery 
life is much shorter than on my gen6, and it gets hotter.

BUT: This thing - gen8 - would get stuck in the acpi_beep before adding this 
to loader.conf. After adding the hint, I have not had a single failure when 
resuming. It's behaving much better than my gen6.

Worth noting that I patched the ig4 driver to allow it to find the I2C device 
(just adding the PCI device IDs to the end of the lists already there), so 
iichid would work and give me a trackpad. Latest drm-devel-kmod works well, 
but install the xf86 intel driver and set "AccelMethod" "sna" in the 
appropriate xorg config file.

/Eirik