On Fri, Apr 08, 2022 at 12:26:24PM +0200, Hans de Goede wrote: > Hi, > > On 4/8/22 12:16, Simon Ser wrote: > > Would it be an option to only support the KMS prop for Good devices, > > and continue using the suboptimal existing sysfs API for Bad devices? > > > > (I'm just throwing ideas around to see what sticks, feel free to ignore.) > > Currently suid-root or pkexec helpers are used to deal with the > /sys/class/backlight requires root rights issue. I really want to > be able to disable these helpers at build time in e.g. GNOME once > the new properties are supported in GNOME. So that distros with > a new enough kernel can reduce their attack surface this way. Yeah but otoh perpetuating a bad interface forever isn't a great idea either. I think the pragmatic plan here is - Implement this properly on good devices, i.e. anything new. - Do some runtime disabling in the pkexec helpers if they detect a modern system (we should be able to put a proper symlink into the drm sysfs connector directories, to make this easy to detect). It's not as great as doing this at compile time, but it's a step. - Figure out a solution for the old crap. We can't really change anything with the load ordering for existing systems, so if the hacked-up compat libbacklight-backlight isn't an option then I guess we need some quirk list/extracted code which makes i915/nouveau/radeon driver load fail until the right backlight shows up. And that needs to be behind a Kconfig to avoid breaking existing systems. Inflicting hotplug complications on all userspace (including uevent handling for this hotpluggable backlight and everything) just because fixing the old crap systems is work is imo really not a good idea. Much better if we get to the correct future step-by-step. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
