1783599 - [Bug]: Qualcomm QM215 SOC , text randomly missing or missing portions of letters/characters.

Status: NEW

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

Description

[Petru-Mugurel Lingurar [:petru]]

From github: https://github.com/mozilla-mobile/fenix/issues/26355.

Steps to reproduce

Qualcomm QM215 SOC , text randomly missing or missing portions of letters/characters.

Happens seemingly randomly , on perhaps 5 -20% of pages.

I've also used the beta and nightly versions to access about:config and force and disable hardware acceleration etc and no difference was seen.

Also used android developer options to change opengl and hardware acceleration options with no difference seen.

Expected behaviour

Text to display normally , as it does in other browsers on QM215 devices.

Actual behaviour

Text is missing or the top or bottom half of text is missing. Happens seemingly randomly.

Device name

Vodafone P11 aka Alcatel 5002x , Qualcomm QM215

Android version

Android 10

Firefox release type

Firefox

Firefox version

103.2.0

Device logs

No response

Additional information

No response

┆Issue is synchronized with this Jira Task

Change performed by the Move to Bugzilla add-on.

Comment 1

[Kevin Brosnan [Ex-Mozilla]]

Attachment: screenshot

Comment 2

[Brad Werth [:bradwerth]]

Jamie, can you reproduce?

Comment 3

[Andrew]

This may be difficult to reproduce, it's a very cheap phone and only gets Android security updates (no driver fixes, bug fixes I assume.) I've used a fare few cheap Android phones with Firefox and this the first time I've seen this issue.

I'm confident other people using Android P11 , Alcatel 5002X devices will have the same issues but I'm guessing people with very cheap devices are unlikely to post bug reports etc.

Is there anything I can do to help?

It has an Adreno 308 GPU if that's known to have any issues.

Comment 4

[Jamie Nicol [:jnicol]]

I've not seen this on other Adreno 308 devices but it's possibly related to the driver version. Could you please attach your about:support information?

Is it always the ends of a piece of text that is missing, like in the photo? Or sometimes random characters in the middle? Perhaps the device has a limit on the number of vertices it can draw.

Comment 5

[Andrew]

Attachment: about support as requested.

It always seems to be at least say 10 characters in a row and not necessarily at the end. Sometimes the top or bottom of the characters are missing.

I've added another screen shot, after the word cheap has disappeared.

about:support below.

Comment 6

[Andrew]

It always seems to be at least say 10 characters in a row and not necessarily at the end. Sometimes the top or bottom of the characters are missing.

I've added another screen shot, after the word cheap has disappeared.

Comment 7

[Andrew]

Attachment: Screenshot_2022-08-09-21-18-58-558.jpg

Comment 8

[Jamie Nicol [:jnicol]]

Thanks! Could you try setting gfx.webrender.debug.disable-batching to true in about:config and see if that helps? (warning - this might make the browser incredibly slow, but may prove or disprove my current theory)

(sorry for initially needinfoing the wrong person, Petru)

Comment 9

[Andrew]

The about:support info may say I'm using the Unlock add-on but that is usually not installed. I've removed it now and the same portion of text is missing.

Comment 10

[Andrew]

I'll try that now.

Comment 11

[Andrew]

That about:config flag has stopped the text missing on the two pages in question. Do you mind leaving this bug open for a little longer as it was intermittent to some extent.

The scrolling is a little slower and jolty but not that different, maybe 20% more laggy.

Comment 12

[Andrew]

Scrolling is pretty stop and start but if you think this is the best result likely you can close this bug.

Thanks for your time it's much appreciated.

Comment 13

[Jamie Nicol [:jnicol]]

Thanks for testing! No, we'll leave this open. I'm surprised it's only 20% more laggy, it's certainly not my intention that you have to leave that flag enabled forever, though feel free to in the interim if the slowdown is preferable to the missing text. But that seems to indicate the problem may be due to using large batches when rendering text.

I would be grateful if you could install this app, upload the report and share the link here.

Comment 14

[Andrew]

Yeah it is more than 20% slower especially on longer pages, the scrolling is the biggest difference.

Here's the link.

http://opengles.gpuinfo.org/displayreport.php?id=6119

Comment 15

[Jamie Nicol [:jnicol]]

Thanks! If you could install this apk and capture the logcat while reproducing the bug that would be a big help!

Comment 16

[Kevin Brosnan [Ex-Mozilla]]

We have some steps about using logcat at https://github.com/mozilla-mobile/fenix/wiki/Logging-Crash-Information#using-adb-logcat-to-get-crash-information

If you need help with those steps feel free to email or chat on https://chat.mozilla.org/#/room/#fenix:mozilla.org

Comment 17

[Andrew]

I added the adb output , this page (https://bugzilla.mozilla.org/show_bug.cgi?id=1783599) hides characters so I used opened it.

Comment 18

[Andrew]

Attachment: adb_output.txt

Comment 19

[Jamie Nicol [:jnicol]]

Hi Andrew, unfortunately I cannot see any of the logs I added in the logcat you attached. Did you use the "geckoview example" application, or just normal Firefox? Sorry I wasn't clear enough, but could you use the geckoview example application?

Comment 20

[Andrew]

(In reply to Jamie Nicol [:jnicol] from comment #19)

Hi Andrew, unfortunately I cannot see any of the logs I added in the logcat you attached. Did you use the "geckoview example" application, or just normal Firefox? Sorry I wasn't clear enough, but could you use the geckoview example application?

Do you have a different link? Is it it hosted at https://ftp.mozilla.org?

I have no idea if I should trust that link.

Comment 21

[Jamie Nicol [:jnicol]]

Fair enough. Unfortunately it's not on ftp.mozilla.org as it's a custom build I made with added logging. You can see a link to the job here: https://treeherder.mozilla.org/jobs?repo=try&selectedTaskRun=AVKKe04tR3KwRWIzOxEX0g.0&revision=73c0f8fa682a6356696af4c982073fce22ff77bf

From that page you can get a link to the APK by selecting the B next to "Android 5.0 Aarch64 opt", then "Artifacts and debugging tools" in the toolbar halfway down the page, then geckoview_example.apk.

You can check the contents of the build by clicking the 73c0f8fa682a link at the top left. That should take you to the commit details. That commit won't be interesting as it just tells CI what jobs to run, in this case build for Android. But you can then click the link next to parent 4580443 which will bring you to the changes I added, here, so you can inspect them yourself.

Comment 22

[Andrew]

It says it can't install, I'm using an ARM v7 version of Android, it's the default Alcatel/Vodafone ROM.

Comment 23

[Andrew]

What does "trojan-source" mean ilon the treeherder URL you posted?

Comment 24

[Andrew]

on the treeherder URL*

Comment 25

[Jamie Nicol [:jnicol]]

Here's a link to a new build I made: https://treeherder.mozilla.org/jobs?repo=try&revision=67fba73c8ab25078cb8f3ba0c83f2684b8478b17

You can download the apk again by clicking on the "B", then "Artifacts and Debugging Tools" then "geckoview_example.apk". You can see the change I made to the code by clicking on the "f601382a306a" next to "log batch size" on the left.

"trojan-source" is a test we run on each push to ensure there aren't bad unicode characters which could be used to sneak in security vulnerabilities. You can find its documentation here: https://firefox-source-docs.mozilla.org/code-quality/lint/linters/trojan-source.html