Keyboard doesn't make the machine up any more

[Stefan Monnier]

Since the last reboot, my desktop doesn't want to listen to my keyboard
any more while sleeping: I can wake it up by pressing the power button
on the actual computer case, but not by pressing a keyboard key.

This has worked fine for several years and I can't remember making any
related change to the machine's config (not sure when was the last time
it was rebooted, so it's possible it was still running an older kernel
from the previous Debian stable).

The machine runs Debian stable.  I checked

    grep . /sys/bus/usb/devices/*/product

and

    grep . /sys/bus/usb/devices/*/power/wakeup

to confirm that the keyboard is marked as "wakeup=enabled", so the
problem apparently comes from elsewhere.  To be double sure, I did:

    for f in /sys/bus/usb/devices/*/power/wakeup; do echo enabled >"$f"; done

and it made no difference.

The keybord is connected via a small unpowered USB hub, so I also tried
to connect the keyboard directly but that did not help either, so the
problem isn't linked to the use of a USB hub.

Here's some further info:

    # uname -a
    Linux pastel 6.1.0-13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.55-1 
(2023-09-29) x86_64 GNU/Linux
    # cat /proc/acpi/wakeup 
    Device  S-state   Status   Sysfs node
    UAR1      S4    *disabled  pnp:00:06
    PS2K      S4    *disabled
    RP01      S4    *disabled  pci:0000:00:1c.0
    PXSX      S4    *disabled
    RP02      S4    *disabled
    PXSX      S4    *disabled
    RP03      S4    *disabled  pci:0000:00:1c.2
    PXSX      S4    *enabled   pci:0000:03:00.0
    RP04      S4    *disabled  pci:0000:00:1c.3
    PXSX      S4    *disabled  pci:0000:04:00.0
    RP05      S4    *disabled
    PXSX      S4    *disabled
    RP06      S4    *disabled
    PXSX      S4    *disabled
    RP07      S4    *disabled
    PXSX      S4    *disabled
    RP08      S4    *disabled
    PXSX      S4    *disabled
    GLAN      S4    *disabled
    EHC1      S4    *enabled   pci:0000:00:1d.0
    EHC2      S4    *enabled   pci:0000:00:1a.0
    XHC       S4    *enabled   pci:0000:00:14.0
    HDEF      S4    *disabled  pci:0000:00:1b.0
    PEG0      S4    *disabled  pci:0000:00:01.0
    PEGP      S4    *disabled
    PEG1      S4    *disabled
    PEG2      S4    *disabled
    #

I don't really know how to interpret the /proc/acpi/wakeup info but IIUC
it seems to say that wakeup is enabled for EHC1, EHC2, and XHC which
I presume represent the various USB controllers present on the motherboard.

Any idea what might be going on, or what else I could check?


        Stefan