Font rendering corrupted when sub-pixel order enabled

Products Support DragonBoard410c
#1

Hi,
I’ve installed xfce4 desktop while using dragonboard-410c-sdcard-developer-buster-528.img sd card image. After reboot the lightdm greeted me with corrupted (unreadable) login dialog. After logging into xfce desktop all looked fine until the font rendering was changed in “Appearance->Fonts” settings. If “Sub-pixel order” is changed from None to RGB or BGR or any other option the fonts get corrupted.

20200608_194633
20200608_1946331024×1153 162 KB

Anybody has seen it or even does have a fix for it (apart just not using sub-pixel rendering)?
Could it be low video memory size? Glxinfo shows only 10Mbytes of video memory size - what’s the way of increasing the dedicated video memory size on APQ8016E ? I’ve looked into DTS and could not find anything useful. Any ideas?

#2

I can also reproduce this bug in the official Linaro release 19.01 with LXQT desktop version 0.13.0. So far my observation is that it seems to affect applications that use GTK. The other ‘native’ LXQT software renders fonts OK.
To reproduce it:

  1. open the Menu->Preferences->Appearance
  2. Select Font item in the left column of icons
  3. Select “None” in Subpixel antialiasing
  4. Confirm and exit the settings dialogue
  5. Reboot the board, then repeat steps 1 - 3, but use “RGB” in subpixel antialiasing
  6. Reboot the board, then open the Wifi selection dialogue, or any other GTK-based program.

font_error01
font_error01982×738 92.6 KB

Any ideas how to fix it would be appreciated.

#3

Could you please try with latest release instead (currently 20.07)?:
https://releases.linaro.org/96boards/dragonboard410c/linaro/debian/latest/

#4

I’ve tried the latest release 20.07 and the result is the same. There are corrupted texts in GTK applications after toggling the Font Subpixel rendering option (and rebooting the board) in settings.

font_error02
font_error02874×547 92.6 KB

It also happens during installation. The installation takes quite a long time, so the screen saver eventually kicks in and after waking up the screen the login screen appears with corrupted fonts. But I’m not concerned about the installer, it’s just for the records.

#5

@molejnik Hi, thanks for the information, I didn’t test with Fon Subpixel rendering option, before we found issues in mesa regarding font rendering and was fix, I will debug the issue.

#6

Thank you for looking into it.

#7

@molejnik I just tested the sd card installer and didn’t see any problem it takes for me ~10 minutes to install from sdcard to mmc, it is reasonable to me.

#8

Hi,

I just tested and looks fine to me using Djavu Font with Subpixel anti-aliasing RGB, Which option you for Font Supixel? and which font did you use?.

Regards,
Anibal

db410c_debian_20.07_fonts
db410c_debian_20.07_fonts1920×1080 144 KB

#9

Hi,
thanks for checking it. In my previous screen shot you can see I also use DejaVu sans font. I don’t think it is caused by the font, nor the font engine (libfreetype2).

Did you do the steps I described to reproduce the issue? The issue does not manifest itself, unles you make the following changes AND open a GTK based software - you dont’ showw any GTK based software on your screen shot. It uses QT widget, which seem to work fine. But GTK does not.