[PATCH] drm/atomic: Take the atomic toys away from X

[Greg KH]

On Fri, May 08, 2020 at 11:06:56AM +0200, Yves-Alexis Perez wrote:
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> On Thu, 2019-09-05 at 20:53 +0200, Daniel Vetter wrote:
> > The -modesetting ddx has a totally broken idea of how atomic works:
> > - doesn't disable old connectors, assuming they get auto-disable like
> >   with the legacy setcrtc
> > - assumes ASYNC_FLIP is wired through for the atomic ioctl
> > - not a single call to TEST_ONLY
> > 
> > Iow the implementation is a 1:1 translation of legacy ioctls to
> > atomic, which is a) broken b) pointless.
> > 
> > We already have bugs in both i915 and amdgpu-DC where this prevents us
> > from enabling neat features.
> > 
> > If anyone ever cares about atomic in X we can easily add a new atomic
> > level (req->value == 2) for X to get back the shiny toys.
> > 
> > Since these broken versions of -modesetting have been shipping,
> > there's really no other way to get out of this bind.
> 
> Hi Daniel and Greg (especially). It seems that this patch was never applied to
> stable, maybe it fell through the cracks?

What patch is "this patch"?

> It doesn't apply as-is in 4.19 branch but a small change in the context makes
> it apply. I'm experiencing issues with lightdm and vt-switch in Debian Buster
> (which has a 4.19 kernel) so I'd appreciate if the patch was included in at
> least that release.

What is the git commit id of the patch in Linus's tree?  If you have a
working backport, that makes it much easier than hoping I can fix it
up...

thanks,

greg k-h