On Fri, Dec 7, 2018 at 9:36 AM Belisko Marek <marek.belisko@xxxxxxxxx> wrote:
Hi Tomasz,
On Fri, Dec 7, 2018 at 6:26 AM Tomasz Torcz <tomek@xxxxxxxxxxxxxx> wrote:
>
> On Thu, Dec 06, 2018 at 10:58:31PM +0100, Belisko Marek wrote:
> > Hi,
> >
> > I'm trying to run qt qml application on intel nuc but when booted from
> > hdd I'll get an eror when app is started:
> >
> > I think it is some kind of timing issue as when booting same image
> > from usb stick application will automatically start while when booting
> > from hdd I get above error. Would be possible to postpone it somehow
> > until DRM display is initialized? Thanks.
>
> This is exactly the problem GDM (GNOME Display Manager) encountered
> few years ago. The solution was devised – your application needs to wait
> until CanGraphical property goes to yes on the seat application is
> using.
Thanks for info. But I'm not suing any GDM (nor X) just qml
application. So IIRC then I need to code something in my application
to wait until
CanGraphical is available?
Yes, to use this method you would need to access logind's D-Bus API. I'm not sure whether QML provides D-Bus access, although Qt does.
I was thinking about
approach that systemd can postpone starting of my application until
DRM is available (not sure is such trigger exists though).
It sounds more like you're looking for a dependency, not a trigger. (Although either would work, I guess.)
In systemd itself, the only available built-in dependency is "device now available in /dev or /sys". For example, you could use this, assuming there's only one card and it's always called "card0":
[Unit]
Requires=dev-dri-card0.device
After=dev-dri-card0.device
(Note: This also needs udev/rules.d/99-systemd.rules to be extended with an apropriate TAG+="systemd".)
Mantas Mikulėnas
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