1572096 - The Browser window flickers when resized with Webrender OFF on Laptops with Nvidia vga

Status: RESOLVED INVALID

(Core :: Graphics: Layers, defect, P3)

Description

[Rares Doghi, Desktop QA]

[Affected versions]:
Nightly 70.0a1

[Affected platforms]:
Platforms: Windows

Precondtions:
Access FF and enter in about:config
Type gfx.webrender.force-disabled set to "true" and verify about:support for Composition (Direct 3D 11 Advanced Layers)

Steps :

1. Launch the Firefox browser with WebRender OFF
2. Maximize the browser window.
3. Grab and Hold the title bar in order to move the browser window down.

Expected Results :
The browser window should resize without flickering.

Actual Results :
The browser windows flickers everytime its resizing.

Please note that this issue could only be reproduced on a Laptop with Nvidia vga GeForce 920m
On desktop pcs with Nvida vgas this issue does not occur.

Comment 1

[Darkspirit]

Type gfx.webrender.all set to "false" and verify about:support for Composition (Webrender)

1. Launch the Firefox browser with WebRender OFF

Small misunderstanding: gfx.webrender.{all, enabled} can only be used to force-enable WebRender.
One needs to set gfx.webrender.force-disabled to true and restart to "Launch the Firefox browser with WebRender OFF".

According to Preconditions you are using WebRender, according to STR not, but then this should be moved to Core::Graphics.
I assume WebRender is still enabled. Could you try to find a regression range (by setting gfx.webrender.all to true) if there is one? Thanks!

Comment 2

[Rares Doghi, Desktop QA]

Attachment: Flickers10.mp4

Comment 3

[Rares Doghi, Desktop QA]

Attachment: Flickers101.mp4

Comment 4

[Rares Doghi, Desktop QA]

Yes that is correct, I just assumed gfx.webrender.all set to false would work as well but yes gfx.webrender.force-disabled set to True is the way to disable Webrender. Thanks Jan.

I will try to find a regression range and then change the component if its not related to webrender. I have also updated the preconditions of this issue.

Comment 5

[Rares Doghi, Desktop QA]

I tried to get a regression range for this issue but it seems that theres not enough data to bisect, still here is the pushlog from the first known bad build:

https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=9419be649effc5bc67eb3d6fce1db46caa7fae7e&tochange=2abcefb31ba7b2a1c573edc5695b772826c6a078

There are 10 bugs related to Webrender but since this issue does not occur on desktop pc's I think the bug causing this issue is this one:

Bug 1549746 - Allow WebRender on nightly for Intel graphics for smaller screen sizes. r=jrmuizel

Please note that the Laptop im working on also has Intel vga and a dedicated GeForce Nvidia 920m

Jeff can you please take a look and let us know if we should move the component away from WebRender to Core:Graphics ?

Comment 6

[Rares Doghi, Desktop QA]

Attachment: aboutsupport.txt

I also attached the information from about:support

Comment 7

[Darkspirit]

For the non-WebRender case (gfx.webrender.force-disabled;true): Can you only reproduce this bug if gfx.direct3d11.use-double-buffering is true, but not if it's false?
For the WebRender case (gfx.webrender.all;true): Can you only reproduce this bug if gfx.webrender.dcomp-win.enabled is true, but not if it's false?
(Restart needed after pref changes.)

Comment 8

[Rares Doghi, Desktop QA]

Hi Jan, I have restested this issue and it seems that this issue only occurs when I set gfx.direct3d11.use-double-buffering = true, If I set this to FALSE it no longer occurs.

Also when Webrender is enabled - gfx.webrender.all = true this issue does not occur.
With gfx.webrender.dcomp-win.enabled set to FALSE theres some kind of flicker of the text but not like in the attached videos and it only occurs when I detach the browser window from the full screen.

I think we can change the component to Core:Graphics what do you think ?

Comment 9

[Darkspirit]

From regression range in comment 5 it looks bug 1549674 is related. If force-enabling WebRender really prevents this issue from occuring, then it might be a Nightly-only bug (pref change: bug 1547775).

Comment 10

[Jessie [:jbonisteel] pls NI]

Hey Sotaro - can you take a look at this later this week or next week?

Comment 11

[Sotaro Ikeda [:sotaro]]

Ok, I am going to take a look.

Comment 12

[Sotaro Ikeda [:sotaro]]

(In reply to Rares Doghi from comment #5)

I tried to get a regression range for this issue but it seems that theres not enough data to bisect, still here is the pushlog from the first known bad build:

https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=9419be649effc5bc67eb3d6fce1db46caa7fae7e&tochange=2abcefb31ba7b2a1c573edc5695b772826c6a078

The following bug is more suspicious.

• Bug 1549674: Use the CompositorWindow to draw to when using DoubleBuffering. r=sotaro

Comment 13

[Sotaro Ikeda [:sotaro]]

Sorry Comment 9 already mentioned about Comment 12

Comment 14

[Sotaro Ikeda [:sotaro]]

It seemed like a driver specific bug. It might be better to blacklist enable DoubleBuffering with d3d compositor.

Comment 15

[Jeff Muizelaar [:jrmuizel]]

Rares, do you still see this in FF 70 in it's default configuration?

Comment 16

[Rares Doghi, Desktop QA]

Nope, this issue does not reproduce with the default configuration in FF beta 70.0b10.

Comment 17

[Gregory Pappas [:gregp]]

It's not possible to turn WebRender off anymore