[PATCH] isdn4linux: Gigaset base driver: improve error recovery

[PATCH] isdn4linux: Gigaset base driver: improve error recovery

The following patch to the Siemens Gigaset base driver adds graceful
recovery for some frequently encountered error conditions, by retrying
failed control requests (eg.  stalled control pipe), and by closing and
reopening the AT command channel when it appears to be stuck.

Signed-off-by: Tilman Schmidt <[email protected]>
Acked-by: Hansjoerg Lipp <[email protected]>
Cc: Karsten Keil <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>