[4.4.70 REGRESSION] Nouveau hangs up at boot

[Takashi Iwai]

Hi,

we've received a bug report about 4.4.70 kernel showing the hang up at
boot.  And, this turned out to be a regression in nouveau driver:
  https://bugzilla.suse.com/show_bug.cgi?id=1043467

I provided a test kernel reverting the last five commits about
nouveau below, and it was confirmed to work.  But still not figured
out which one actually breaks.

e4add1cf6b4154804350c3385c6d447cff3570de
    drm/nouveau/tmr: handle races with hw when updating the next alarm time
        commit 1b0f84380b10ee97f7d2dd191294de9017e94d1d upstream.

9d78e40f5f41ad1db1849f8d15acbda99d0871b4
    drm/nouveau/tmr: avoid processing completed alarms when adding a new one
        commit 330bdf62fe6a6c5b99a647f7bf7157107c9348b3 upstream.

5e07724c28f4e06fe42dd5b58bb6f9dd56510567
    drm/nouveau/tmr: fix corruption of the pending list when rescheduling an alarm
        commit 9fc64667ee48c9a25e7dca1a6bcb6906fec5bcc5 upstream.

27f82df2f02688c51d2c1d9f624cc0c5b8a62661
    drm/nouveau/tmr: ack interrupt before processing alarms
        commit 3733bd8b407211739e72d051e5f30ad82a52c4bc upstream.

3819271d8a5f4c6e0c8f71c339e44e2efbe40710
    drm/nouveau/therm: remove ineffective workarounds for alarm bugs
        commit e4311ee51d1e2676001b2d8fcefd92bdd79aad85 upstream.


Ben, is this a known problem?  Or is there any fixup?
The kernel back trace found in the bugzilla report shows the issue in
nvkm_timer_alarm_trigger(), at least.


thanks,

Takashi