nouveau/ NV11: 3.12 freezes if X.org is started headless

[Ilia Mirkin]

On Tue, Nov 26, 2013 at 8:35 PM, Stefan Lippers-Hollmann <s.L-H at gmx.de> wrote:
> Hi
>
> On Wednesday 27 November 2013, Ilia Mirkin wrote:
>> On Tue, Nov 26, 2013 at 7:18 PM, Stefan Lippers-Hollmann <s.L-H at gmx.de> wrote:
>> > Hi
>> >
>> > On Tuesday 26 November 2013, Ilia Mirkin wrote:
>> >> On Tue, Nov 26, 2013 at 6:03 PM, Stefan Lippers-Hollmann <s.L-H at gmx.de> wrote:
>> >> > v3.11 is fine, with and without monitor attached.
>> >> > v3.12 is fine as long as X.org isn't started (but may fail to reboot
>> >> >       cleanly). If a monitor is connected I don't observe any problems,
>> >> >       it freezes without a monitor connected.
>> >> > v3.13-rc1-95-gb975dc3 appears not to freeze without a monitor anymore
>> >> >       (I didn't confirm that it's fine with a monitor attached), but I
>> >> >       end up with the following Oops (this is before X.org is started).
>>
>> One more idea -- try it with nouveau.runpm=0 -- I've had some odd
>> results with it on my older cards (but I don't remember hangs, but I
>> also didn't spend a lot of time on it, just plopped the option in and
>> moved on). This is a feature that got in in 3.12, and is really the
>> only major nouveau-affecting change in that kernel for your card
>> revision.
>
> You're spot on, that does the trick.

Great to hear!

>
> # cat /sys/module/nouveau/parameters/agpmode
> -1
> # cat /sys/module/nouveau/parameters/runpm
> 0
>
>   v3.13-rc1-95-gb975dc3
> + http://cgit.freedesktop.org/~darktama/nouveau/commit/?id=0397aaaa009092427dc60aea8b3c21c00526d8ba
> + nouveau.runpm=0
> is now stable, with and without a monitor attached; as is
>
>   3.12.1 || v3.12.1-62-g4615252 (stable-queue.git)
> + nouveau.runpm=0
>

Dave, looking at the code, it seems like runtime pm should only be
getting activated by default for optimus systems. Stefan's is clearly
not one of those, neither is mine. Unfortunately I have no clue how
the runtime pm subsystem works, but it seems like runtime_suspend()
may be getting called directly, e.g. if there are no monitors attached
to nouveau, perhaps as a result of nouveau_crtc_set_config in
dispnv04/crtc.c. Does the same if (runpm == -1 && !optimus) return
-EBUSY check belong in the runtime_suspend callback?

  -ilia