Comment 22 for bug 453365

I had similar worries about race conditions, but this code path is supposed
to be happening so rarely, that the race conditions would probably be even
rarer.

That being said, that does seem like a cleaner solution. File a different
bug and we'll track it there. It's just going to need some good testing to
make sure that we get it right.

On Mon, Dec 14, 2009 at 15:26, Anders Kaseorg <email address hidden> wrote:

> > --- debian/gdm.upstart 2009-12-11 05:36:55 +0000
> > +++ debian/gdm.upstart 2009-12-14 20:12:34 +0000
> > @@ -9,7 +9,9 @@
> > start on (filesystem
> > and (graphics-device-added fb0 PRIMARY_DEVICE_FOR_DISPLAY=1
> > or drm-device-added card0 PRIMARY_DEVICE_FOR_DISPLAY=1
> > - or stopped udevtrigger))
> > + or stopped udevtrigger)
> > + or build-successful MODULE=nvidia
> > + or build-successful MODULE=fglrx)
> > stop on runlevel [016]
> >
> > emits starting-dm
>
> I’m a little worried that this has race conditions:
> • If build-successful fires before the graphics device is ready, gdm
> startup may be triggered too early (is this a problem?).
> • If build-successful fires between the time X fails to module and the time
> gdm finishes failing to start, the event will be lost entirely.
>
> Maybe one way this could be solved is to leave gdm the way it was and
> add a dummy task to the nvidia and fglrx packages to block gdm from
> starting up before the module is available. This avoids any race
> conditions that involve trying to start the gdm job multiple times, and
> also seems more neatly modular:
>
> start on starting gdm and (build-successful MODULE=nvidia or build-failed
> MODULE=nvidia)
> task
> exec /bin/true
>
> (Given that use case, perhaps build-failed should not actually be a
> separate event? It might be nicer to emit events like
> dkms-build MODULE=nvidia RESULT=successful
> dkms-build MODULE=nvidia RESULT=failed
> so that one can wait for dkms-build MODULE=nvidia without needing to
> indicate which.)
>
> Should I file a separate bug?
>
> --
> dkms should start before gdm if needed for video driver
> https://bugs.launchpad.net/bugs/453365
> You received this bug notification because you are a bug assignee.
>

--
Mario Limonciello
<email address hidden>