1707833 - Tiles not rendered intermittently

Status: RESOLVED INCOMPLETE

(Core :: Graphics: WebRender, defect)

Description

[:gerard-majax]

Attachment: about:support

From time to time, some tiles might not render correctly, leaving parts of the UI missing.

One example would be with the hamburger menu:

• click hamburger menu
• menu displays but upper left part is missing
• after a few seconds or cursor moves, the missing part is rendered

As visible in attached about:support, this is on Ubuntu 20.10 / Wayland with Intel GPU

Comment 1

[Dzmitry Malyshau [:kvark]]

Looks like direct composition is off here, and WR is enabled. This means, hamburger menu is rendered with software WR (SW-WR), while the main content is rendered with HW-WR, and they are composited separately.
Is the issue happening only on the hamburger menu? Or is it occasionally on the content as well?
Some screenshots would be handy.

Comment 2

[:gerard-majax]

(In reply to Dzmitry Malyshau [:kvark] from comment #1)

Looks like direct composition is off here, and WR is enabled. This means, hamburger menu is rendered with software WR (SW-WR), while the main content is rendered with HW-WR, and they are composited separately.

As much as can tell, I have flipped back all WebRender related prefs to their defaults values, so if the menu is rendered with theh wrong compositor, either its a bug or expected :)

Is the issue happening only on the hamburger menu? Or is it occasionally on the content as well?

I have only seen it intermittently on chrome, not content. And I dont remember outside of the menu.

Some screenshots would be handy.

I agree, but catching the issue for long enough to be able to take a screenshot has proven to be challenging to far.

Comment 3

[gwarser]

Attachment: 20210502_221907_1.jpg

I see something like this. Cannot be captured on screenshot - repainted on key press.

Comment 4

[:gerard-majax]

(In reply to gwarser from comment #3)

Created attachment 9219755 [details]
20210502_221907_1.jpg

I see something like this. Cannot be captured on screenshot - repainted on key press.

Good catch, this is similar to what I see in term of location and size ; although in my case content is empty and not something else like in your case but I guess it's system-dependant at this point.

I see you caught that on an addon popup ; while opening this tab I got a repro that happened as well on the Multi-Container addon dropdown.

Comment 5

[:gerard-majax]

This disappeared after some time on my previous intel-based laptop, and i've switched to a new laptop (with an amd gpu).