On Tue, Sep 22, 2020 at 4:14 PM Daniel Stone daniel@fooishbar.org wrote:
On Tue, 22 Sep 2020 at 15:04, Daniel Vetter daniel.vetter@ffwll.ch wrote:
On Tue, Sep 22, 2020 at 3:36 PM Marius Vlad marius.vlad@collabora.com wrote:
Gentle ping. I've tried out Linus's master tree and, and like Pekka, I've noticed this isn't integrated/added.
Defacto the uapi we have now is that userspace needs to ignore "spurious" EBUSY.
This really, really, really, bites.
I think we need a guarantee that this never happens if ALLOW_MODESET is always used in blocking mode, plus in future a cap we can use to detect that we won't be getting spurious EBUSY events.
I really don't want to ever paper over this, because it's one of the clearest indications that userspace has its timing/signalling wrong.
Ok so the hang-up last time around iirc was that I broke igt by making a few things more synchronous. Let's hope I'm not also breaking stuff with the WARN_ON ...
New plan: - make this patch here only document existing behaviour and enforce it with the WARN_ON - new uapi would be behind a flag or something, with userspace and everything hanging off it.
Thoughts?
Cheers, Daniel