macsmc-input: skip spurious BTN_TOUCHID events on s2idle entry

[areofyl]

The SMC fires a spurious BTN_TOUCHID press+release within ~1ms of entering s2idle, which triggers pm_wakeup_dev_event and immediately wakes the system back up.

This patch skips the first 2 button events after pm_prepare. The counter resets on pm_complete so normal button handling is restored after resume.

Kernel log showing the spurious events (stock fairydust, no patch):

Jul 03 17:07:51 nimbus kernel: PM: suspend entry (s2idle)
Jul 03 17:07:52 nimbus kernel: macsmc 23e400000.smc: RTKit: syslog message: apComms.cpp:354: SMC HID Event: 01 06 01
Jul 03 17:07:52 nimbus kernel: macsmc 23e400000.smc: RTKit: syslog message: apComms.cpp:354: SMC HID Event: 01 06 00
Jul 03 17:07:52 nimbus kernel: PM: suspend exit

01 06 01 / 01 06 00 = BTN_TOUCHID press/release. This pattern repeats on every suspend attempt.

Tested on M1 MacBook Air (J313), fairydust 6.18.10.

[oliverbestmann]

With this patch, my m1pro does not wake up automatically if i open the lid (with no external screen connected). It did that before. I then need to press the power button for ~1 second for it to turn on again. Previously a short tap on the power button was enough.

[areofyl]

With this patch, my m1pro does not wake up automatically if i open the lid (with no external screen connected). It did that before. I then need to press the power button for ~1 second for it to turn on again. Previously a short tap on the power button was enough.

Yeah I'm sorry about that. Lid wake is a known limitation of s2idle on Apple Silicon. Workqueues are frozen during suspend so the kernel can't poll the lid sensor. If it seemed to work before, it was likely a coincidence (the SMC fires spurious events that can wake the system around the same time). There's no clean fix for this without upstream changes to how the SMC delivers lid events.

[jannau]

On which device are you seeing this? I've never noticed this before and just tested this with uart and no_console_suspend on M1 Macbook Air and 14-inch Macbook Pro without seeing any issues. There is a single lid close event when closing the lid which results in s2idle (if configured so). Then nothing happens until the lid is opened which results in a single lid open event.

Please provide a description on how you noticed the issue and how your device behaves ideally with relevant kernel logs around suspend / lid events. I assume you added a log statement in macsmc_input_event(). Please provide the patch as well.

[areofyl]

This is on an M1 MacBook Air (t8103) running Gentoo with the fairydust kernel. I don't have UART set up so my logs are from journalctl, but I can try to get better captures.

The issue I hit was the SMC firing a spurious BTN_TOUCHID press+release about 1ms after entering s2idle, which would immediately wake the system back up. The ignore counter in my patch skips those first 2 events so the system stays asleep.

I didn't realize lid events were being delivered reliably via notifications on other machines. On mine they seemed inconsistent, which is why I added MSLD polling. If lid wake works fine through the existing event path on MBA and 14-inch MBP, this polling approach is probably wrong and I should narrow the fix to just the spurious button handling.

I'll try to get proper logs with the stock kernel showing the spurious wake and post them here.

[areofyl]

You were right. Lid events are delivered fine via notifications on my machine. I tested with evtest on stock fairydust and SW_LID events show up immediately on lid open/close:

Event: time 1783123862.440018, type 5 (EV_SW), code 0 (SW_LID), value 1
Event: time 1783123867.155555, type 5 (EV_SW), code 0 (SW_LID), value 0

I've dropped the MSLD polling, debounce, and sysfs attribute entirely and narrowed this to just the spurious BTN_TOUCHID fix. The SMC fires 01 06 01 + 01 06 00 (BTN_TOUCHID press+release) within ~1ms of every s2idle entry, which triggers pm_wakeup_dev_event and wakes the system immediately:

Jul 03 17:07:51 nimbus kernel: PM: suspend entry (s2idle)
Jul 03 17:07:52 nimbus kernel: SMC HID Event: 01 06 01
Jul 03 17:07:52 nimbus kernel: SMC HID Event: 01 06 00
Jul 03 17:07:52 nimbus kernel: PM: suspend exit

This reproduces every time on my M1 MacBook Air (J313) running fairydust 6.18.10. The fix just skips the first 2 button events after pm_prepare.