Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900

From: Pavel Machek
Date: Tue Jul 04 2017 - 11:09:26 EST


> >>>> Are you sure it doesn't probe? It fails the omapdss_stack_is_ready()
> >>>> check?
> >>>
> >>> It appears the reason was that I didn't have
> >>>
> >>> I think that's wrong. I don't own an analog TV, so why should I enable
> >>> such option to get device's built-in display working?
> >>
> >> Indeed. Unfortunately I don't have a solution for that.
> >>
> >> DRM doesn't support adding devices after probe. So at omapdrm probe time
> >> we have to decide which displays to use. In the dts file, n900 defines
> >> the lcd and analog tv. omapdrm sees those, and, of course, must wait
> >> until their respective drivers have probed. If you don't have the
> >> display driver enabled, it's never loaded and omapdrm never probes as it
> >> keeps waiting for those.
> >
> > Could you at least print some kind of message early in the boot ("omapdrm
> > is waiting for drivers for display x and y")?
> That could be quite spammy. omapdrm will defer probe if the displays are
> not present, and the deferred probing machinery will then cause a new
> omapdrm probe later. That can happen a lot of times before the drivers
> are there.

Well doing printk just once should not be a problem...?
(cesky, pictures)