I am using a raspberry pi model b 512 MB with an Edimax EW-7811Un wifi stick and the raspberry pi camera. Power adapter has 2A/5V. OS is latest raspbian, kernel 3.12.25+. For the wifi stick, I have disabled the power management, also I have set up a cronjob pinging my router once every minute.
However the following happens: After several hours (15 and 18 hours the last times) I can't reach the raspberry pi anymore using wifi. Syslog shows, that the pi is still running. I can't find hints on wifi problems in the syslog, though.
Any ideas, what else I could try? Thanks!
Update:
I have to correct myself. I can still ping the pi, but other connections are not possible, e.g. SSH using Putty ends up with "Server unexpectedly closed network connection" after several seconds. Very strange. Any ideas on this? Thanks!