diff -up hplip-3.9.10/prnt/backend/hp.c.device-reconnected hplip-3.9.10/prnt/backend/hp.c --- hplip-3.9.10/prnt/backend/hp.c.device-reconnected 2009-11-03 21:45:10.000000000 +0000 +++ hplip-3.9.10/prnt/backend/hp.c 2009-11-04 16:25:30.719129509 +0000 @@ -645,6 +645,7 @@ int main(int argc, char *argv[]) HPMUD_DEVICE hd=-1; HPMUD_CHANNEL cd=-1; int n, total=0, retry=0, size, pages; + int consecutive_failures=0; enum HPMUD_RESULT stat; char *printer = getenv("PRINTER"); @@ -809,11 +810,24 @@ int main(int argc, char *argv[]) { exit_stat = BACKEND_STOP; /* stop queue */ goto bugout; + } + + if (++consecutive_failures == 5) + { + /* hpmud_write_channel has failed several times in + * succession but the Device ID-based status says + * the printer is happy. Time to face the fact that + * the device has probably reconnected, and our USB + * channel is invalidated. */ + + BUG("ERROR: device reconnected?"); + goto bugout; } } else { /* Data was sent to device successfully. */ + consecutive_failures = 0; if (pa.pjl_device) { /* Laserjets have a large data buffer, so manually check for operator intervention condition. */