1993838 - WebRender becomes blurry on complex pages at high resolution (5120x1440) with NVIDIA eGPU on Linux (X11)

Status: UNCONFIRMED

(Core :: Graphics: WebRender, defect)

Description

[Tyler Cook]

Attachment: support.json

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36

Steps to reproduce:

1. Hardware: NVIDIA RTX 3060 Ti (eGPU) connected to a 5120x1440 monitor.
2. Software: Pop!_OS 22.04 (X11 session), NVIDIA Driver 580.82.09, Firefox/Firefox-based browser as a Flatpak.
3. Launch the browser with hardware acceleration forced on using the environment variable: MOZ_X11_EGL=1.
4. Navigate to a graphically complex web application (e.g., aistudio.google.com after logging in).
5. Resize the browser window from a small size to fullscreen.
6. Observe: The webpage content becomes blurry when the window becomes large.
   Navigate to a simpler website (e.g., msn.com, reddit.com) and observe that the content remains sharp at all window sizes.

Actual results:

When using a hardware-accelerated WebRender session, the entire content of a graphically complex webpage (e.g., a web application) becomes blurry and appears downscaled when the browser window is stretched to a large size on a 5120x1440 ultrawide monitor. Simpler websites do not exhibit this behavior.

This issue is not present in Google Chrome, which proves the system, driver, and hardware are working correctly and the bug is specific to the WebRender engine.
Attempts to disable WebRender using MOZ_WEBRENDER=0 are ignored by the browser, which continues to use WebRender.
Forcing the GPU to "Prefer Maximum Performance" via nvidia-settings/xorg.conf has no effect on the bug.
Please find the full about:support JSON output attached.

Expected results:

The webpage content should remain sharp and rendered at native resolution at all window sizes, regardless of the complexity of the page.

Comment 1

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

The Bugbug bot thinks this bug should belong to the 'Core::Graphics: WebRender' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Lee Salzman [:lsalzman]]

Glenn, ideas what's going on here?

Comment 3

[Glenn Watson [:gw]]

Are you able to provide some screenshots of blurry / non-blurry you're seeing?

Comment 4

[Tyler Cook]

Attachment: notBlurry.png

Comment 5

[Tyler Cook]

Attachment: blurry.png

Comment 6

[Tyler Cook]

Yes, I just uploaded notBlurry and blurry PNG files.

Comment 7

[Glenn Watson [:gw]]

It might be that it's hitting the maximum texture size for a child render task and downscaling it. Will see if anyone on the team has hardware they can repro with.