645333 - Dotted border-bottom and border-top slower with hardware acceleration enabled

Status: RESOLVED WORKSFORME

Description

[John Lee]

User-Agent:       Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.2a1pre) Gecko/20110326 Firefox/4.2a1pre
Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.2a1pre) Gecko/20110326 Firefox/4.2a1pre

With hardware acceleration enabled, elements with "border-bottom: 1px dotted;" and "border-top: 1px dotted;" take much longer to render. Performance is restored when hardware acceleration is disabled.

Reproducible: Always

Steps to Reproduce:
1. Load test cases.
2. Switch to another tab and switch back.
3. Switch to another application and switch back.
Actual Results:  
Firefox will take unreasonably longer to render the "border-bottom" and "border-top" testcases, upon loading, upon tab switching and upon application switching. Firefox performs normally with the "border", "border-left" and "border-bottom" testcases.

Tested on Firefox 4.0 and Minefield built on 26-Mar-2011.

Expected Results:  
Firefox performing normally with all dotted border testcases.

Comment 1

[John Lee]

Created attachment 522111 [details]
Simple DIV dotted border-bottom testcase

Comment 2

[John Lee]

Created attachment 522112 [details]
Zipped testcases for dotted borders

Comment 3

[Boris Zbarsky [:bzbarsky, bz on IRC]]

Bas?

Comment 4

[Ali Juma [:ajuma]]

I'm not able to reproduce this on Nightly on Windows 7 (with hardware acceleration enabled). Please reopen if you're still seeing this.