Comment 22 for bug 1449401

Still bad for now:
$ git bisect log
# bad: [4f37b5b1578d66c7d6787e180bddeb631f5adee5] UBUNTU: Ubuntu-3.16.0-36.48
# good: [cfe550c2824b7917963795cac393998ac56ceb5c] UBUNTU: Ubuntu-3.16.0-34.47
git bisect start 'Ubuntu-3.16.0-36.48' 'Ubuntu-3.16.0-34.47'
# bad: [fcf73471bf9fc7f60f10253c03739e49cf1f463e] drm/radeon: do a posting read in rs600_set_irq
git bisect bad fcf73471bf9fc7f60f10253c03739e49cf1f463e
# bad: [611f6fde150fc2523b2074d40f4290af2e6e87ab] udp: only allow UFO for packets from SOCK_DGRAM sockets
git bisect bad 611f6fde150fc2523b2074d40f4290af2e6e87ab
# bad: [d89a0fb687d7c9cedd62b26f982258679cf70268] of: add optional options parameter to of_find_node_by_path()
git bisect bad d89a0fb687d7c9cedd62b26f982258679cf70268
# bad: [bf4787bab6ea96aaba9768c98e8d679e4ad47694] drm/ast: switch to using CACHED by default for sysram
git bisect bad bf4787bab6ea96aaba9768c98e8d679e4ad47694

I see potentially interesting commits in:
$ git log --oneline Ubuntu-3.16.0-34.47..
3329a6e drm/i915/bdw: Cleanup pre prod workarounds
d960a0b drm/i915/bdw: Apply workarounds in render ring init function
a4b15d0a drm/i915: call lpt_init_clock_gating on BDW too
090271c drm/i915/bdw: 3D_CHICKEN3 has write mask bits
d13c2ab KEYS: request_key() should reget expired keys rather than give EKEYEXPIRED
d745351 UBUNTU: Start new release