Improve wifi_scan_config_t documentation (IDFGH-11475)

[llamasoft]

Answers checklist.

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

General issue report

The documentation surrounding wifi_scan_config_t needs some additional clarification.

Specifically:

• The behavior of .channel = 0 scanning all channels is undocumented.
• When scanning all channels, does it respect the current wifi_country_t?
• When using .scan_type = WIFI_SCAN_TYPE_ACTIVE:
  • How is the value of .scan_time.passive used?
  • Does probe request broadcast time count towards .scan_time.active?
  • How is the scan time determined using .scan_time.active.min and .scan_time.active.max?
• When using .scan_type = WIFI_SCAN_TYPE_PASSIVE is .scan_time.active ignored?
• What is the time unit of .home_chan_dwell_time? Milliseconds? FreeRTOS ticks?
• When .channel = 0 and .home_chan_dwell_time = 0, does the scan visit the home channel between consecutive channel scans?

[igrr]

How is the scan time determined using .scan_time.active.min and .scan_time.active.max

Just a note, this one of the questions is answered in https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/wifi.html#scan-configuration

[mhdong]

Hi @llamasoft

1. When scanning all channels, does it respect the current wifi_country_t? Yes, the scanned channel must meet the requirements of the country code. For detailes, please refer to https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/wifi.html#wi-fi-country-code

[Sherry616]

Thanks for reporting, we will close this issue. Feel free to reopen if have more updates. Thanks for using our Espressif product!