drm:intel_power_well_disable: disabling PW_2 - Shutdown/reboot incomplete (Halt) on the last step of the process.

Tried my best to write an err title, but It seems it does not give an "err" ID per se. Please change the title as needed or tell me how to do it.

❯ uname -a
Linux localhost 6.6.30-gentoo #1 SMP PREEMPT_DYNAMIC Wed May 15 14:11:51 CEST 2024 x86_64 Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz GenuineIntel GNU/Linux

❯ lspci -vnn -d 8086:3ea0
00:02.0 VGA compatible controller [0300]: Intel Corporation WhiskeyLake-U GT2 [UHD Graphics 620] [8086:3ea0] (rev 02) (prog-if 00 [VGA controller])
	Subsystem: Lenovo WhiskeyLake-U GT2 [UHD Graphics 620] [17aa:2294]
	Flags: bus master, fast devsel, latency 0, IRQ 144, IOMMU group 0
	Memory at 601c000000 (64-bit, non-prefetchable) [size=16M]
	Memory at 4000000000 (64-bit, prefetchable) [size=256M]
	I/O ports at 2000 [size=64]
	Capabilities: [40] Vendor Specific Information: Len=0c <?>
	Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
	Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable- 64bit-
	Capabilities: [d0] Power Management version 2
	Capabilities: [100] Process Address Space ID (PASID)
	Capabilities: [200] Address Translation Service (ATS)
	Capabilities: [300] Page Request Interface (PRI)
	Kernel driver in use: i915

I've been suffering a shutdown/reboot freeze in two of my Thinkpads, one of them is a x270, the other one is a x390 since kernel 6.7 till recent kernels. The last one that don´t have this freeze problem is 6.6.30. Neither 6.7.x till 6.9.x kernels on the Gentoo portage tree solved this problem, and I think something changed in 6.7 series that is still present in recent ones.

The bug itself is shown as this: Everything seems to properly shutdown (screen, keyboard, ...) but in the end both laptops still powered (I can hear the fan in both and x270 has power light switched on, x390 bloq mayus light is blinking and power light switched on). I still have to press both laptops power button to do a completely poweroff.

I haven't found on the web, nor bugzilla anyone pointing to this issue on theese kernel versions, but some similar behaviour in some degree that I cannot confirm it is the very same problem.

I filled a bug on Gentoo specific kernel bugzilla: https://bugs.gentoo.org/929240 Then in kernel bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=218904 Then they redirected here.

There, they asked me to do a git bisect between versions (I used the git latest version to do it) and after many configure, compilations, installs, reboots and git bisects narrowed it to this commit:

❯ git bisect good
e046d156249140711a08ff27473591c74ef90814 is the first bad commit
commit e046d156249140711a08ff27473591c74ef90814
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Tue Aug 29 14:39:17 2023 +0300

    drm/i915/hdmi: Use connector->ddc everwhere
    
    We already populate connector->ddc for HDMI ports, but
    so far we've not taken full advantage of it. Do that by
    eliminating a bunch of intel_gmbus_get_adapter() lookups.
    
    Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20230829113920.13713-10-ville.syrjala@linux.intel.com
    Reviewed-by: Jani Nikula <jani.nikula@intel.com>

 drivers/gpu/drm/i915/display/intel_ddi.c  |  3 +--
 drivers/gpu/drm/i915/display/intel_hdmi.c | 37 +++++++++++--------------------
 2 files changed, 14 insertions(+), 26 deletions(-)'

Attached you will find "drm.debug=0xe log_buf_len=4M ignore_loglevel" dmesg 6.9.3 kernel logs. dmesg

All in, this issue looks like a regression. Ask for whatever you need, If I don't know how to get it I will study to get them.

Many thanks in advance.

Best