1826601 - [R600] Resizing window produces hall of mirrors effect in new areas

Status: NEW

(Core :: Graphics: WebRender, defect)

Description

[Kestrel]

Attachment: Camera recording of mirror effect while resizing window

STR:

1. Start with MOZ_ENABLE_WAYLAND=1 on Ubuntu 22.10 with HW-WR on low-spec graphics hardware (AMD RS880/R600).
2. Resize the window several times from the top-left corner.

There is a delay in the content catching up to the window and a hall of mirrors effect is rendered in the new areas on the right and bottom sides. Screen capture fails to record this effect, only showing black areas.

It is much more severe with HW-WR on low spec hardware but it can also be seen with SW-WR as a subtle flicker on the window edges.

Does not happen on XWayland where window resizing is synchronous with the content.

Regression window:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=798c43651cb145ef813aa9ece37b6d965afc315f&tochange=658c01aa35228543db3728393f7b2bfa626249df

Likely regressed by Bug 1734368.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

:stransky, since you are the author of the regressor, bug 1734368, could you take a look?

For more information, please visit auto_nag documentation.

Comment 2

[Martin Stránský [:stransky] (ni? me) (PTO, back on Feb 17)]

We can't use sync update as may block whole browser and makes off main thread rendering obsolete.
I tested that on AMD RX 6600 and also on 9 years old laptop with integrated Intel HD 530 and I don't see the effects there.
I'd say it's R600 specific bug then.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1734368