Black screen resume from suspend

[Ottavio Caruso <ottavio2006-usenet2012%yahoo.com@localhost>]

Hi,

I had a nice and long chat last Saturday with Riastradh (thanks!) and,
before filing a bug report, I'd like the list's advice on this issue.

My laptop is a beat-up Thinkpad E130 on its last legs, so I don't rule
out hardware failures, however I have a dejavu moment and I'm pretty
sure I had the same problems many years ago with another Thinkpad.

Soon after giving the suspend to RAM command (sudo sysctl -w
hw.acpi.sleep.state=3), the laptop does indeed suspend; however, on
resume (opening the lid or pressing the power button, I'm left with a
black screen, with the a big static cursor on the top left. The
keyboard doesn't work. I can't get to open a virtual terminal
(CTRL+ALT+9n)) and all I can do is to press the power button and
restart the machine.

This happens regardless of whether I am in Xorg or just a standard console.

Riastradh suggested the following steps:

# drvctl -S i915drmkms0; sleep 5; drvctl -Q i915drmkms0

This crashes the laptop and triggers a spontaneous reboot.

I set up a partition as dump device and enabled logging but it doesn't
leave a crash dump in /var/crash.

There are worrying lines is dmesg, such as:

[  1780.037511] wsdisplay0: emergency X server detach
[  1780.457853] warning:
/usr/src/sys/external/bsd/drm2/dist/drm/i915/intel_uncore.c:554:
WARN_ON(domain->wake_count)
{drm:netbsd:intel_set_cpu_fifo_underrun_reporting+0x29c} *ERROR*
uncleared fifo underrun on pipe A
{drm:netbsd:intel_cpu_fifo_underrun_irq_handler+0x64} *ERROR* CPU pipe
A FIFO underrun
{drm:netbsd:intel_set_pch_fifo_underrun_reporting+0x14e} *ERROR*
uncleared pch fifo underrun on pch transcoder A
{drm:netbsd:cpt_irq_handler+0x1dd} *ERROR* PCH transcoder A FIFO underrun

All pointing to intel drm.

From rc.log:

[running /etc/rc.d/savecore]
Checking for core dump...
savecore: no core dump

Then Riastradh suggested booting with a kernel from current
(https://nycdn.netbsd.org/pub/NetBSD-daily/HEAD/202210080110Z/amd64/binary/kernel/netbsd-GENERIC.gz),
which I did. With the new kernel. There is an improvement. The above
command (drvctl -S i915drmkms0; sleep 5; drvctl -Q i915drmkms0) does
not crash the laptop. I can manage to get the display back playing
with CRTL+ALT-2. However the black screen on resume from suspend
remains.

I have also modified /boot.cfg:

menu=Boot no i915:rndseed /var/db/entropy-file;userconf disable i915*;boot

But apparently all i915* modules are still loaded.

I am posting the last dmesg after the incident:
https://termbin.com/e48tq

The latest rc.log:
https://termbin.com/cxz4

And Xorg.log.old.
https://termbin.com/az5r

Any suggestions are welcome.

I am planning to buy another 2nd hand Thinkpad with a similar Intel
chipset and I'd like to know if I'm going to have the same problem.

Thanks.

-- 
Ottavio Caruso

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