On 24 August 2017 at 01:57, Dave Airlie <airlied@xxxxxxxxx> wrote: >> Yeah, maybe it's time to disconnect the "default display device" idea >> from the VGA arbiter. I have no idea what (if any) dependencies X has >> on the legacy VGA resources. I assume X works fine on power, where it >> sounds like those resources are rarely or never available. > > The question on non-x86 archs, is what is the correct device to default to. > > On x86 we use the legacy VGA resources as a pointer, as this is the device > the BIOS appeared on at boot so hopefully should be one you can see stuff on. > > On non-x86 I've no idea how to decide if there are multiple devices, maybe the > firmware needs to tag something for the kernel if there are. Otherwise > you'd just > be picking something in probe order. > > I think the idea of these patches is to separate default display > device from the arbiter. > > X uses the arbiter on x86 if required (it's horrible, and it's rare we > have to nowadays), > but for finding the default device it justs uses the sysfs boot_vga flag. > Part of the problem is that X refuses to start if there is only one display device to begin with in case it hasn't taken ownership of the VGA legacy resources.
