I have noticed a weird WiFi bug with OS X Yosemite. This has never happened in any previous OS X that I have used. I have a Early 2013 Macbook Pro with Retina display 13 and I updated to Yosemite a day after it launched. I usually do not shut down my laptop and just keep it in sleep. After the update, sometimes when the laptop wakes up from sleep WiFi is completely switched off. On trying to turn it on I get the following message in console:
22/10/14 1:41:11.000 pm kernel: ARPT: 1911.087562: wl0: _wlc_ioctl: dead chip, off bar0[0xffffffff]
Upon restart the WiFI icon becomes a grey icon with a cross mark and says either "No hardware installed" or "WiFi not configured".
The only solution I have found till now is an SMC reset. But with the frequency of this happening is quite high and is frustrating to always shutdown and do an SMC reset. Is anyone else facing similar issues? And does anyone know of a fix without a restart ?