1325867 - artifacts when editing large text areas (such as in mediawiki)

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Alain Knaff]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0
Build ID: 20161213204132

Steps to reproduce:

1. Edited a large page in mediawiki
2. Paste text (one word or two) from another application into page
3. Delete part of just pasted text
4. Or just move cursor around...


Actual results:

During edit artifacts occasionally appear:
- random text becomes half bolded,
- thin vertical lines show up
- thick black horizontal bars cover part of the text
- some letters are doubled, i.e. show up bother where they were before the edit and where they are now.
- the vertical "cursor" bar leaves "traces" (i.e. still shows up where it used to be, even after moving it to someplace else)

Usually typing another character or clicking makes the text normal again...
Shift-Alt-F12 (no compositing) also fixes the display, when continuing to edit, the display "spoils" again (i.e. Shift-Alt-F12 fixes damage that is already there, but doesn't prevent later re-occurrence).


Expected results:

Text should display without artifacts. Letters and cursor marks should not leave any "traces" or "droppings"

Comment 1

[Alain Knaff]

Problem does not happen when graphics acceleration is switched off. However, unlike a similar bug in thunderbird, it still occurs when merely limiting acceleration to bitblitting (blt):

/usr/share/X11/xorg.conf.d/99-intel.conf:

Section "Device"
        Identifier "intel"
#       Option "ShadowFB" "off"
#       Option "NoDRI"
        Option "NoAccel"
#       Option "AccelMethod" "UXA" # Still shows bug in thunderbird
#       Option "AccelMethod" "blt" # Works ok in thunderbird, but not firefox
#       Option "AccelMethod" "SNA" # Still shows bug in thunderbird
EndSection

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Can you reproduce this on a more recent version of Firefox?

Comment 3

[Wayne Mery (:wsmwk)]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #2)
> Can you reproduce this on a more recent version of Firefox?

something on the order of version 50 or newer would be nice. Which I am also going to mention in bug 1325854

Comment 4

[Alain Knaff]

In the meantime, I found the real reason: a broken GTK2 "oxygen" Engine. After switching to qtcurve, the issue disappeared, even with HWA on again.