Olimex Support Forum

OLinuXino Android / Linux boards and System On Modules => A20 => Topic started by: anverx on November 07, 2019, 04:36:21 pm

Title: New 10" display shows green instead of white
Post by: anverx on November 07, 2019, 04:36:21 pm

Recently olimex has updated the display controller board. When connected to A20 Lime, it renders fonts differently, specifically fonts with 1 pixel wide vertical lines show up green instead of white.  This was a direct drop-in replacement, older displays were fine. 

(https://lh3.googleusercontent.com/eQ5-5-zuVWINhQ9Avx-f69cGT7xeRJbfm-trKT3_Q-AiInV-FlT3erFr93hR53EtnHBBak0kk2Zvbd06fpGhWKIhq7fXpbOgvTv-TLXvNZDmhlVgu1UwJChrcx6V9LS0gCe68WfJ5SM=w2400)

How do i get this fixed?
Title: Re: New 10" display shows green instead of white
Post by: olimex on November 08, 2019, 10:55:19 am
Can you give us more details?
What power supply? Which Linux image are you using?
We tested random board + LCD from our stock and there are no such problems, so you must do something wrong, can you please take picture of your setup? 
Title: Re: New 10" display shows green instead of white
Post by: anverx on November 08, 2019, 01:11:25 pm
- We are using power supplies from reputable brands like Mean Well and Nordic Power, 5v 2A.
- System info:
    The system is pretty much out of the box Debian 9.
    uname:
Linux assembly-10139 4.9.0-6-armmp-lpae #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) armv7l GNU/Linux 

    Xorg.log header:

[    12.180] X Protocol Version 11, Revision 0
[    12.180] Build Operating System: Linux 4.9.0-4-armmp-lpae armv7l Debian
[    12.180] Current Operating System: Linux assembly-10139 4.9.0-6-armmp-lpae #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) armv7l
[    12.180] Kernel command line: sunxi_ve_mem_reserve=0 sunxi_g2d_mem_reserve=0 sunxi_fb_mem_reserve=16 console=tty1 quiet
[    12.181] Build Date: 16 October 2017  09:48:39AM
[    12.181] xorg-server 2:1.19.2-1+deb9u2 (https://www.debian.org/support)
[    12.181] Current version of pixman: 0.34.0


- Here are some pictures of our setup

(https://lh3.googleusercontent.com/mX6IWnqhH6yBPbt7xkFAue4AWeWKxPh2O_sBqexmD77XCYGDNrGOW8bWNTnBer5dqTRWN56eX_cgjUI-1XnoG6RAGrPemhs9IXgkzckUHCtQaD96DoDxq8Hf-tuP2EoOvUoN-RNXKeE=w2400)
(https://lh3.googleusercontent.com/raUm7I-zxNxGF4IXZvbgY4oISJDTFSxFM7PJMXB_U7G34UJEd46CfUzuFotnsNMAP4TyeQF1RkXatAgqdPsaLjTPh0ODay1iaKwBY7DvY1oxP8euXjOqrywBeA1z0LF93-QCiqkCpag=w2400)

It feels like the issue is specific to lines that are 1 pixel wide.  Bigger fonts seem to render ok.  Could this be about subpixel rendering?
Title: Re: New 10" display shows green instead of white
Post by: LubOlimex on November 11, 2019, 03:04:00 pm
It could be anything but we have few ideas:

- we also changed the 10 inch displays some times ago and new displays required new software configuration or certain glitches were expected; this was detailed here: https://www.olimex.com/Products/OLinuXino/LCD/LCD-OLinuXino-10/resources/LCD-OLinuXino-10-errata.pdf

- remove the blue radio board just for the test; we've seen certain boards affecting the data lines of the display, maybe it bugs colors; remove it or place it further away from the LCD board and test again

- make sure to test a few displays since it can be bent cables causing glitches

- test with the latest official Olimex image without any changes - this is not optimal but will show if it is a software issue or hardware issue; this is meant only as a test; the latest images can be found here:

ftp://staging.olimex.com/Allwinner_Images/A20-OLinuXino/1.latest_mainline_images/bionic/images/

We also have Debian 10 images but they are server images without X so I can't recommend them for this test of the displays, yet if you are interested for future work consider checking them here:

ftp://staging.olimex.com/Allwinner_Images/A20-OLinuXino/1.latest_mainline_images/buster/images/
Title: Re: New 10" display shows green instead of white
Post by: anverx on November 12, 2019, 08:39:08 pm
- the nfc reader doesn't affect this.  It can be disconnected or removed the effects don't change.
- i've tested couple more displays from the batch, all seem to behave the same below are couple of pictures from a different unit
- I'll try to boot up that ubuntu image, but so far i've only gotten black screen, is meant to work with LCD out of the box?
- Here are couple of close ups:
this is an xterm
(https://lh3.googleusercontent.com/Z4KuwwbhPvExtbJPNeDIcn5iaxG6m6dBOuMxD-BIBF4TflaM0PNikQDFW-2AdlJA4ZuaYK69qWKwT9lyXGFFFCI875hcuBR6nrf72cIJeijjbR3UzXQTue9sY5J7Bqi6Tzp0znPnF6w=w2400)

and this is from console, white color is rendered correctly but colored prompt is broken
(https://lh3.googleusercontent.com/vo5GBbKz8e1qnhW5NtRGl0NRHqln3qCNQv70Ao5CA5TsmeSEjltq0jPcYC08BwmgSVuo7vZSHfVatK_fsilg4pMDiEoR3QU4RKlYJLIAB_0Q7S2DuCtaAEzuUPk7J7KjEndf7-9ZLK4=w2400)

So this might not be related to subpixel rendering, or does console driver do it too?
Title: Re: New 10" display shows green instead of white
Post by: LubOlimex on November 13, 2019, 01:37:43 pm
> - I'll try to boot up that Ubuntu image, but so far I've only gotten black screen, is meant to work with LCD out of the box?

Usually yes, but if it doesn't start, you can also configure it manually - you need to interrupt the boot process to stay in u-boot (at the point where it say press any key). This might require serial connection to the debug pins of the board or HDMI screen. You then type:

olinuxino monitor set LCD-OLinuXino-10

then save with command "saveenv" and reset with "reset". More info can be found here: https://www.olimex.com/wiki/ArmbianHowTo#Selecting_video_output
Title: Re: New 10" display shows green instead of white
Post by: anverx on November 15, 2019, 06:46:57 pm
I can confirm that most recent ubuntu desktop image looks fine, both in xterm and in chromium.  I'll have to redo our production image basing on the latest debian server, hopefully it has all the same drivers.

I was under impression that `apt-get update/upgrade` gets the latest kernel and xserver, looks like it doesn't
Title: Re: New 10" display shows green instead of white
Post by: ring on January 09, 2020, 12:04:16 pm
Quote from: anverx on November 08, 2019, 01:11:25 pm- We are using power supplies from reputable brands like Mean Well and Nordic Power, 5v 2A.
- System info:
    The system is pretty much out of the box Debian 9.
    uname:
Linux assembly-10139 4.9.0-6-armmp-lpae #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) armv7l GNU/Linux 


    Xorg.log header:

[    12.180] X Protocol Version 11, Revision 0
[    12.180] Build Operating System: Linux 4.9.0-4-armmp-lpae armv7l Debian
[    12.180] Current Operating System: Linux assembly-10139 4.9.0-6-armmp-lpae #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) armv7l
[    12.180] Kernel command line: sunxi_ve_mem_reserve=0 sunxi_g2d_mem_reserve=0 sunxi_fb_mem_reserve=16 console=tty1 quiet
[    12.181] Build Date: 16 October 2017  09:48:39AM
[    12.181] xorg-server 2:1.19.2-1+deb9u2 (https://www.debian.org/support)
[    12.181] Current version of pixman: 0.34.0



- Here are some pictures of our setup for how to measure ring size (https://www.howtomeasureringsize.net).

(https://lh3.googleusercontent.com/mX6IWnqhH6yBPbt7xkFAue4AWeWKxPh2O_sBqexmD77XCYGDNrGOW8bWNTnBer5dqTRWN56eX_cgjUI-1XnoG6RAGrPemhs9IXgkzckUHCtQaD96DoDxq8Hf-tuP2EoOvUoN-RNXKeE=w2400)
(https://lh3.googleusercontent.com/raUm7I-zxNxGF4IXZvbgY4oISJDTFSxFM7PJMXB_U7G34UJEd46CfUzuFotnsNMAP4TyeQF1RkXatAgqdPsaLjTPh0ODay1iaKwBY7DvY1oxP8euXjOqrywBeA1z0LF93-QCiqkCpag=w2400)

It feels like the issue is specific to lines that are 1 pixel wide.  Bigger fonts seem to render ok.  Could this be about subpixel rendering?

have you a guide for centos 7?.