Messages in this thread | | | Date | Fri, 16 Feb 2024 11:00:17 +0200 | Subject | Re: [PATCH 1/2] drm/tidss: Fix initial plane zpos values | From | Tomi Valkeinen <> |
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Hi,
On 13/02/2024 13:39, Daniel Stone wrote: > Hi, > > On Tue, 13 Feb 2024 at 10:18, Marius Vlad <marius.vlad@collabora.com> wrote: >> On Tue, Feb 13, 2024 at 11:57:59AM +0200, Tomi Valkeinen wrote: >>> I haven't. I'm quite unfamiliar with Weston, and Randolph from TI (cc'd) has >>> been working on the Weston side of things. I also don't know if there's >>> something TI specific here, as the use case is with non-mainline GPU drivers >>> and non-mainline Mesa. I should have been a bit clearer in the patch >>> description, as I didn't mean that upstream Weston has a bug (maybe it has, >>> maybe it has not). > > Don't worry about it. We've had bugs in the past and I'm sure we'll > have more. :) Either way, it's definitely better to have the kernel > expose sensible behaviour rather than weird workarounds, unless > they've been around for so long that they're basically baked into ABI.
Yeah, that's always a worry. I do hope that no user of tidss expects the plane zpos values to be the current funny ones. But we'll probably find out when I merge this =).
>>> The issue seen is that when Weston decides to use DRM planes for >>> composition, the plane zpositions are not configured correctly (or at all?). >>> Afaics, this leads to e.g. weston showing a window with a DRM "overlay" >>> plane that is behind the "primary" root plane, so the window is not visible. >>> And as Weston thinks that the area supposedly covered by the overlay plane >>> does not need to be rendered on the root plane, there are also artifacts on >>> that area. >>> >>> Also, the Weston I used is a bit older one (10.0.1), as I needed to go back >>> in my buildroot versions to get all that non-mainline GPU stuff compiled and >>> working. A more recent Weston may behave differently. >> >> Right after Weston 10, we had a few minor changes related to the >> zpos-sorting list of planes and how we parse the plan list without having >> a temporary zpos ordered list to pick planes from. >> >> And there's another fix for missing out to set out the zpos for scanout >> to the minimum available - which seems like a good candidate to explain >> what happens in the issue described above. So if trying Weston again, >> please try with at least Weston 12, which should have those changes >> in. > > Specifically, you probably want commits 4cde507be6a1 and 58dde0e0c000. > I think the window of breakage was small enough that - assuming either > those commits or an upgrade to Weston 12/13 fixes it - we can just ask > people to upgrade to a fixed Weston. > >>> Presuming this is not related to any TI specific code, I guess it's a >>> regression in the sense that at some point Weston added the support to use >>> planes for composition, so previously with only a single plane per display >>> there was no issue. > > That point was 12 years ago, so not that novel. ;)
Hmm, so do I understand it right, the plane code from 12 years back supposedly works ok, but somewhere around Weston 10 something broke, but was fixed with the commits you mention above?
Tomi
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