I did a clean install of Fedora 22 on my laptop. It will intermittently hang on boot. It gets as far as the Fedora logo and stops. I have to do a hard boot and try again. It usually takes several tries before it boots successfully.
I've checked boot.log but didn't see anything clues there. I wanted to turn of verbose messages during startup, but I can't find my grub.conf (I'm guessing that file no longer exists).
Once it hangs and I press the power button once, the Fedora logo goes away and these two messages appear.
[drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR uncleared pch fifo underrun on pch transcoder A
[drm:interl_pch_fifo_underrun_irq_handler [i915]] *ERROR PCH transcoder A FIFO underrun
Any suggestions as to what to try/check?