Device unable to go to light sleep with PCNT unit enabled without glitch filter (IDFGH-14231)

[lptr]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

In ESP-IDF 5.3.1 and before, the APB frequency lock was only used if the glitch filter was enabled for a PCNT unit. This allowed the device to enter light sleep even when a PCNT unit was enabled (but without a glitch filter).

In ESP-IDF 5.3.2 the commit 33f8207 introduced new behavior, and the lock is always installed and used, even if the glitch filter is not enabled.

This means that since 5.3.2 the device cannot enter light sleep when a PCNT unit is enabled, even if it uses no glitch filter.

The commit comment says "fix" but I found no record of what problem this is fixing.

The documentation in 5.3.2 still says the lock is installed lazily only when a glitch filter is present:

 *       So this function will lazy-install a PM lock internally when the power management is enabled. With this lock, the APB frequency won't be changed.

https://github.com/espressif/esp-idf/blob/v5.3.2/components/esp_driver_pcnt/include/driver/pulse_cnt.h#L128

[Kainarx]

Thank you for your feedback. We've left some documentation unchanged. In fact the APB clock is the function clock for the PCNT peripheral, not only for the glitch filter. The previous version was actually not correct.