When user is active (eg. writing SQL query), phpMyAdmin should avoid session timeout as this can have unpleasant results.
Use case:
I think phpMyAdmin should make background keepalive requests to the server when user is doing some activity (eg. typing a query).
Just open up config.inc.php in the root phpMyAdmin directory and add this setting
$cfg['LoginCookieValidity'] = <your_new_timeout>;
This won't help in case user is not submitting anything, just using an interface.
See also https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=754649
Implemented: https://github.com/phpmyadmin/phpmyadmin/pull/1355