Canon Scanner Detection Issues when the Scanner is in Sleeping Mode.

SANE Version : 1.0.28 (libsane-dev:amd64 1.0.28+git20190913-bionic0)

Affected API : extern SANE_Status sane_get_devices (const SANE_Device *** device_list..)

Platform : x86_64

OS : Ubuntu 18.04 (18.04.1-Ubuntu SMP)

Scanner Model : Cannon DR-X10C II

Connection : USB

How to test : Wait (10 min) until the scanner gets into 'sleeping' mode, try detect connected scanner by using sane_get_devices..

Behavior : The API seems to wake the scanner up, however API returns false, and SANE APIs beyond that point will not work.

Reproducibility: Always

Possible cause : wait_scanner(scanner*) from "canon_dr.c" is using '500 msec' timeout which is too short for waiting the scanner reply when waking up.