1507534 - Sometimes sides of GSlides slide don't paint (MAX_TILES_PER_REQUEST)

Status: RESOLVED FIXED

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

Description

[Andrew Overholt [:overholt]]

With WebRender on, if I navigate between slides in this presentation:

https://docs.google.com/presentation/d/1EhHvUL9kGUdSweSxvrVdlHh1lbas1_hSWDwbJHY5iL0/edit#slide=id.g46e9efbc38_1_603 (MoCo only; sorry)

I sometimes get the sides (maybe 20% each left and right) painted and then they'll "un-paint" (they get a checkerboard background but only within the area where the slide content should be).

This doesn't happen with WebRender disabled.

Comment 1

[Andrew Overholt [:overholt]]

Today's nightly on Windows 10 on a Surface Laptop (v1) - Intel graphics. Perhaps more pronounced (actually, maybe *only* reproducible) on an external monitor (connected via DisplayPort from the Surface Hub in case it matters).

Comment 2

[Andrew Overholt [:overholt]]

https://docs.google.com/presentation/d/16rOoM28g_hVL6wEoTqMjEb1_4w9DxmVNUkda6xfSoyk/edit#slide=id.g47179e5844_0_0 is a blank-ish public "presentation" that exhibits the behaviour I've described here when changing between slides.

Comment 3

[Andrew Overholt [:overholt]]

It seems to happen only on my external monitor and the window size that causes it is ~3711x1764.

Comment 4

[Andrew Overholt [:overholt]]

Attachment: illustrative screenshot

Comment 5

[Kartikaya Gupta (email:[e-mail])]

That's interesting. I don't think we draw an actual checkerboard pattern anywhere in Gecko or WR. So most likely GSlides is putting that there. This might need some digging around in JS code to figure out where the checkerboard is coming from and why WR might be triggering it.

Comment 6

[Jeff Muizelaar [:jrmuizel]]

I wonder if this is the same problem as bug 1494164

Comment 7

[Jeff Muizelaar [:jrmuizel]]

Sotaro's patch from bug 1494164 seems to fix this for me.

Comment 8

[Sotaro Ikeda [:sotaro]]

I confirmed that the STR in comment 0 hit MAX_TILES_PER_REQUEST.

Comment 9

[Sotaro Ikeda [:sotaro]]

:overholt, can you re-check if the problem is addressed on nightly?

Comment 10

[Andrew Overholt [:overholt]]

I can't make it happen anymore (confirmed on my external monitor) so 👍 from my end :)

Comment 11

[Sotaro Ikeda [:sotaro]]

Thanks!