1835252 - Characters missing in displayed text (Firefox, Thunderbird), other missing parts (SeaMonkey)

Status: RESOLVED INCOMPLETE

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

Description

[Jerry Peek]

Attachment: mozilla-firefox_memory-report.json.gz

Steps to reproduce:

Similar bugs happen in Thunderbird and sometimes SeaMonkey. (This has happened in many versions of Firefox, Thunderbird and sometimes SeaMonkey. This problem doesn't appear on other browsers [Opera, Edge, DuckDuckGo].) Run the program for "a while" (sorry, I don't have an exact measure: sometimes a number of hours, sometimes days). Usually Windows 10 Resource Monitor shows over 40% Used Physical Memory. This has been happening intermittently for months or years. (Sorry, writing a bug report takes lots of time; I have trouble finding enough time to do it.) **NOTE PLEASE: I have many screenshots and memory reports, but bugzilla will only let me attach one of them. I will put them on my website and list URLs in "What happened?" box. If that's not satisfactory, please tell me how to submit them.)

Actual results:

Some characters on a web page (Firefox) or in an email message header or body (Thunderbird) won't appear; there will be empty white space there. Sometimes black rectangular areas will appear. The problem may disappear or change if I refresh the page. The "missing" characters will re-appear if I hold down the left mouse button and slide the cursor over the parts of the text that don't display.

I have more screenshots and memory reports than the single file this form will allow. So I've put them in a private directory (folder) on my personal website. The folder has no index.html file, only the files I list below. It's an Apache server mantained by 1&1 IONOS; I believe the files are secure from attackers. All screenshots were made on the top monitor of a two-monitor display system.

a) https://www.jpeek.com/tmp/bugzilla/mozilla-problems-1.png - SeaMonkey thumbnail preview and taskbar at bottom of Windows 10 desktop

b) https://www.jpeek.com/tmp/bugzilla/mozilla-problems-2.png - SeaMonkey random scattered rectangles that aren't in the right place

c) https://www.jpeek.com/tmp/bugzilla/mozilla-problems-3.png - Thunderbird missing characters in email message body

d) https://www.jpeek.com/tmp/bugzilla/mozilla-problems-4.png - Firefox missing characters in web page

e) https://www.jpeek.com/tmp/bugzilla/mozilla-problems-5.png - Windows 10 Resource Monitor window

f) https://www.jpeek.com/tmp/bugzilla/mozilla-firefox_memory-report.json.gz - Firefox memory report

g) https://www.jpeek.com/tmp/bugzilla/mozilla-seamonkey_memory-report.json.gz - SeaMonkey memory report

h) https://www.jpeek.com/tmp/bugzilla/mozilla-thunderbird_memory-report.json.gz - Thunderbird memory report

Expected results:

I should always see all of the text in a web page or email message. Black rectangles shouldn't appear.

Comment 1

[Jerry Peek]

The files on the server are unwritable (Linux mode 444); the folder doesn't allow deletions, additions, renaming (Linux mode 555). If you're concerned that the files are booby-trapped, you might use a download-only tool like wget(1) that only saves the files, doesn't display them.

Comment 2

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

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Win32' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[Ray Kraesig [:rkraesig]]

I suspect these are either two different bugs or a hardware issue that Chromium happens to miss (Opera, Edge, and DuckDuckGo are all essentially the same browser as far as rendering is concerned), but I'll leave it to the Graphics team to make that determination.

Comment 4

[Darkspirit (doesn't receive bugmail until AWS SES supports IPv6 DNS)]

Thanks for the report! Please open about:support, click on "Copy text to clipboard" and paste it here.

Comment 5

[Jerry Peek]

Attachment: Output of about:support in Firefox 113.0.2 (64-bit)

Darkspirit wrote: Thanks for the report! Please open about:support, click on "Copy text to clipboard" and paste it here [link to click]. This is the report for: Firefox 113.0.2 (64-bit). The output type I chose was "Copy raw data to clipboard". I pasted the data into Windows Notepad, then saved it as a file, then browsed for the file in the "File:" window at the top of this form. (Note: Because I'm reporting for two different browsers and Thunderbird, I'll try to paste output for those in the same way.)

Comment 6

[Jerry Peek]

Attachment: Output of about:support in SeaMonkey 2.53.16 (I think it's 64-bit)

Darkspirit wrote: Thanks for the report! Please open about:support, click on "Copy text to clipboard" and paste it here [link to click]. This is the report for: SeaMonkey 2.53.16 (I think it's 64-bit). The output type I chose was "Copy raw data to clipboard". I pasted the data into Windows Notepad, then saved it as a file, then browsed for the file in the "File:" window at the top of this form. (Note: I'm reporting for two different browsers and Thunderbird. I've already sent data from Firefox. In the next report I'll try Thunderbird.)

Comment 7

[Jerry Peek]

Attachment: Text from "Troubleshooting Information" for Thunderbird 102.11.2 (64-bit)

Darkspirit wrote: Thanks for the report! Please open about:support, click on "Copy text to clipboard" and paste it here [link to click]. I wasn't sure how to do this in Thunderbird 102.11.2 (64-bit), so I opened the Help menu and chose "More Troubleshooting Information", then I chose "Copy text to clipboard". I pasted the data into Windows Notepad, then saved it as a file, then browsed for the file in the "File:" window at the top of this form. Note: In the section showing accounts, I've replaced the incoming and outgoing server domain names with "HIDDEN". (Note: I'm reporting for two different browsers and Thunderbird. I've already sent data from Firefox and SeaMonkey. In this report I'm sending info for Thunderbird.)

Comment 8

[Teodor Tanasoaia [:teoxoy]]

I'm not sure what the severity of this should be.

Comment 9

[Ashley Hale [:ahale]]

The GPU in your system has not had recent driver updates (last updated 2016), these rendering bugs (the squares that are showing the wrong image) is likely after the video driver has had to restart for some reason.

If you'd like to experiment, here are some things you can try to get it working better:

• Go to about:config in each app and turn off the pref gfx.webrender.compositor, this may or may not help but if it makes the rendering artifacts go away that would certainly be interesting to know. This requires restarting the app after changing the setting. Testing this only on Firefox should be suffiicent.
• A more complete solution would be to use software rendering, which is controlled by the pref gfx.webrender.software - setting that to true will make these apps not use the GPU to render web content, which should completely avoid artifacting issues, this also requires restarting the app to take effect.

Regarding memory usage, do you have an animated theme?

Comment 10

[Jerry Peek]

Attachment: Screenshot of Firefox window using profile #1 (see report written 6/16/23)

Comment 11

[Jerry Peek]

Attachment: Screenshot of Firefox window using profile #2 (see report written 6/16/23)

Comment 12

[Jerry Peek]

Thanks for the clear troubleshooting steps, Ashley Hale [:ahale]. I'm not surprised that the GPU is so old. :( No, I'm not using an animated theme. I rarely play videos. I have two monitors.

I tried this only in Firefox, which is the browser use most. I attached two screenshots above. One shows Firefox profile #1; the other shows profile #2. (I have four profiles. I often open main windows first, and sometimes open private windows.) In each profile window, I used GIMP to paste text onto the screenshot describing what steps I did in that profile. A summary:

A. I turned off the pref gfx.webrender.compositor. Immediately some letters disappeared from the second box. I had just started each instance of Firefox and had also started the computer recently. Letters usually don't disappear this soon after I've started the system. Also, the User Physical Memory (in Windows Resource Monitor) was 35%; the problem usually seems to happen when memory usage is more like 45-50%. (I'm not sure if either of those are actually the cause of the missing text.)

B. In in both profiles, gfx.webrender.compositor was set to false and gfx.webrender.software was set to true. I closed all Firefox windows, then opened the same two windows. I left the "Advanced Preferences" tab open in each browser window (each profile) as a reminder. A quick look told me that the text was all visible. (I didn't look at every word in the Preferences window because I don't know what they should all say.)

Note that this problem usually happens at about the same time in Firefox and Thunderbird. It usually happens later in SeaMonkey, if at all. It never happens in Opera or Edge. Also note that I'm running these in a standard user account (non-administrator) on the latest version of Windows 10 (updated a couple of days ago).

If there's some other measurement I can make before the problem happens anywhere (Firefox, Thunderbord, SeaMonkey) -- and, of course, after -- I'd be glad to.

Comment 13

[Ashley Hale [:ahale]]

Thanks for attempting to repro with those prefs, but I must emphasize that it is important to restart the browser after toggling these settings as simply editing them can only cause refreshes of the window and does not actually change the behavior until the browser is restarted.

There are only 3 meaningful combinations here:

• gfx.webrender.software = true - this is our ultimate fallback, with some performance impact. I expect this to work properly.
• gfx.webrender.software = false, gfx.webrender.compositor = false - this would be a really interesting data point to analyze because if it fixed the issue it would have less performance impact for you, i.e. we would be more inclined to set users with your GPU to use this pref with a blocklist in future to give them a better experience but not all the way to software fallback mode.
• gfx.webrender.software = false, gfx.webrender.compositor = true - this is the normal state of Firefox so I assume this is the affected case.

There are other things that would likely make the issue subside briefly like clicking the "Trigger Device Reset" button in about:support but that's not a useful workaround :)

Comment 14

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

A needinfo is requested from the reporter, however, the reporter is inactive on Bugzilla. Given that the bug is still UNCONFIRMED, closing the bug as incomplete.

For more information, please visit BugBot documentation.