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Participant
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Registered: ‎05-20-2018

configure display setting for desktop environment

Hello. 

I developed my zynq board in order to display linux desktop. But it shows a corrupted image (random like pixels) on my screen. However I know it is my Desktop Environment because when I use "cat /dev/fb0 > myFile"  and save content of what is showing on LCD and display it on another device that its linux is working by some default config and use "cat myFile > /dev/fb0", the showing image is exactly correct desktop.

I edited my "xorg.conf" file but did not gain any reasonable result:

 

Section "Device"
    Identifier      "/dev/fb0" EndSection

Section "Monitor"
    Identifier      "myMonitor"
    HorizSync       36.6-48
    VertRefresh     66.8-84
    Mode    "1920x1080"
            DotClock        148.500000
            HTimings        1920 2008 2052 2200
            VTimings        1080 1084 1089 1125
            Flags   "+HSync" "+VSync"
    EndMode EndSection

Section "Screen"
    Identifier      "myScreen"
    Monitor         "myMonitor"
    Device          "/dev/fb0"
    Driver          "fmrfb"
    DefaultDepth    24  SubSection "Display"
        Depth           24
        Modes           "1920x1080"
    EndSubSection EndSection

What is my problem? Is it from "xorg.conf" file or other configurations should be edited?

thank you.

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Mentor
Mentor
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Registered: ‎06-16-2013

Re: configure display setting for desktop environment

Hi @mojtaba.ahmadi

 

Would you share Xorg.log file to investigate the route cause ?

 

Best regards,

 

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Registered: ‎05-20-2018

Re: configure display setting for desktop environment

@watari

 

here it is:

 

 

[    14.980]
X.Org X Server 1.11.3
Release Date: 2011-12-16
[    14.980] X Protocol Version 11, Revision 0
[    14.981] Build Operating System: Linux 2.6.38-1209-omap4 armv7l Ubuntu
[    14.981] Current Operating System: Linux localhost.localdomain 3.15.0-xilinx #1 SMP PREEMPT Tue Oct 9 16:45:47 IRST 2018 armv7l
[    14.981] Kernel command line: console=ttyPS0,115200 root=/dev/mmcblk0p2 rw earlyprintk rootfstype=ext4 rootwait devtmpfs.mount=0
[    14.981] Build Date: 05 April 2012  12:04:28AM
[    14.981] xorg-server 2:1.11.4-0ubuntu10 (For technical support please see http://www.ubuntu.com/support)
[    14.981] Current version of pixman: 0.24.4
[    14.981]    Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
[    14.982] Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    14.982] (==) Log file: "/var/log/Xorg.0.log", Time: Thu Jan  1 00:00:14 1970
[    15.000] (==) Using config file: "/etc/X11/xorg.conf"
[    15.000] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[    15.016] Parse error on line 25 of section Screen in file /etc/X11/xorg.conf
        This section must have only one of either Identifier or Driver line.
[    15.017] (EE) Problem parsing the config file
[    15.017] (EE) Error parsing the config file
[    15.017]
Fatal server error:
[    15.017] no screens found
[    15.017]
Please consult the The X.Org Foundation support
         at http://wiki.x.org
 for help.
[    15.017] Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[    15.017]
[    15.018]  ddxSigGiveUp: Closing log
[    15.018] Server terminated with error (1). Closing log file.
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Participant
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Registered: ‎05-20-2018

Re: configure display setting for desktop environment

@watari

 

 changed my xorg.conf in this manner and error got OK:

 

Section "Device"
    Identifier    	"/dev/fb0"
EndSection

Section "Monitor"
    Identifier    	"myMonitor"
    HorizSync       36.6-48
    VertRefresh     66.8-84
    Modeline "1280x720"  74.25  1280 1390 1430 1650  720 725 730 750 +hsync -vsync -csync 
EndSection

Section "Screen"
    Identifier    	"myScreen"
    Monitor        	"myMonitor"
    Device        	"/dev/fb0"
#    Driver	  		"fmrfb"
    DefaultDepth    24
	SubSection "Display"
        Depth    		24
        Modes     		"1280x720"
    EndSubSection
EndSection 

Section "ServerLayout"
  Identifier   "mylayout"
  Screen       "myScreen"
EndSection

but know I can not see anything on my screen. the LCD turns off after running startx. I guess I should change the driver of frame buffer to my own one. but how can I do that?

with driver = "fmrfb" in screen section it gives error in xorg.log.

how can I set driver?

what should I do?

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Mentor
Mentor
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Registered: ‎06-16-2013

Re: configure display setting for desktop environment

Hi @mojtaba.ahmadi

 

I have some questions.

 

Q1) Did you already describe configration file to load library file for fmrfb ? Or, did you include libraly file for fmrfb ?

Q2) What kind of LCD do you use ? Use LCD panel (1280x720) ? Also, how do you connect it ? By FPD link (LVDS) ? By parallel interface ? By HDMI ?

Q3) How do you decide sync polarity ? Why do you decide hsync as positive and vsync as negative ?

 

If my understainding is correct, I suggest the following.

 

- Add libraly path for fmrfb in ld.conf

- Remove csync (maybe conposit sync) polarity setting in Xorg.conf

- Remove comment for fmrfb in Xorg.conf

- Make sure pixel clock frequency.

 

If hardware design and parameter setting are correct, I guess it will be fine.

 

> it shows a corrupted image (random like pixels) on my screen

 

Also, would you share me this picture ?

It has help to resolve this issue.

 

Best regards,

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Registered: ‎05-20-2018

Re: configure display setting for desktop environment

@watari tnx for your attention

 

about your questions:

1) In my Kernel compilation I had included fmrfb driver. but did not include it in other configuration. what should I do about that? I searched about ld.conf but did not find anything. 

2) I connect my LCD by HDMI to my zynq board.

3) In fact I do not have enough information about hsync and vsync configs and these settings are based on what were logged on Xorg.0.log of working version of linux. although I removed them from xorg.conf but no effect!

 

about your tips:

- how should I add library path to ld.conf? what is it?

- how to make sure about clock frequency?

 

the corrupted image is this (you can also see the LCD I am using):

1 - Copy.png

 

I should mention that this appear when I set my resolution 1920x1080 in device tree, but when change it to 1280x720 the screen is black but turns on.

 

and this is the picture of my FPGA design in vivado:

Capture.PNG

 

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Mentor
Mentor
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Registered: ‎06-16-2013

Re: configure display setting for desktop environment

Hi @mojtaba.ahmadi

 

Here is my quick answer.

I will reply detail answer for your question as soon as possible.

 

After confirm your design diagram, I suspect the followings.

Would you make sure them ?

 

- Did you set correct parameter as 1280x720 on VDMA ?

  => It seems that you set wrong parameter on VDMA from your picture.

- Did you set correct parameter as BT1120 or YUV422 for external HDMI Tx ?

  => You should set correct parameter as BT1120 or YUV422. (From your design.)

 

BTW, does your LCD panel has an EDID rom ?

If yes, can you change or write EDID value ?

I suggest to prepare an EDID rom for supporting 1280x720@60Hz.

 

Best regards,

 

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Re: configure display setting for desktop environment

@watari 

 

1- I changed video format from RGB to YUV4:2:2 in AXI4-Stream to Video Out and replaced the bitstream with last one. now the screen does not even turn on!

2- about Video Mode, in Video Timing Controller (v_tc) ip, it was set to 720p that contains 1280x720 too.

3- how should I use EDID rom in this project?

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Registered: ‎06-16-2013

Re: configure display setting for desktop environment

Hi @mojtaba.ahmadi

 

> fmrfb

Sorry. I don't have an enough experience about petalinux design flow.
However, I have some experiences about linux.
It was related with linux experience in previous my explanation.
In this case, should add driver setting file in /etc/ld.so.conf.d/ .
But it depends on how to build linux system.

> EDID rom

I guess, you use like following system.

Zynq board -> HDMI receiver board -> LCD panel

In this case, HDMI receiver board has an EDID rom.

Also, here is my question.

Q1) How to convert video data to HDMI signal ? Use an external HDMI Tx ?
Q2) If you achive to output video data to LCD panel, it might be easy to change the way from HDMI to FPD link.

Best regard,

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Registered: ‎05-20-2018

Re: configure display setting for desktop environment

Dear @watari

 

yes my system as the way you said.

 

about your questions:

1) I just use axi4 to video out IP for video signals that its format is RGB and when I change it to YUV4:2:2 as said before, the LCD does not turn on at all. although I am trying to use some IPs to convert RGB to YUV4:2:2 to test.

2) at current design (video out IP with RGB output format) the LCD turns on however shows some nonsense pixels. it means I achieve data on output but encoding may have problem.

 

I should mention that I am trying to run Linux and your experience is helpful for me.

thank you for you attention.

 

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Registered: ‎06-16-2013

Re: configure display setting for desktop environment

Hi @mojtaba.ahmadi

 

> however shows some nonsense pixels.

 

Would you share me this picture ?

 

Best regards,

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Registered: ‎05-20-2018

Re: configure display setting for desktop environment

@watari

 

I have shared it before in previous answers:

LCD image.png

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Mentor
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Registered: ‎06-16-2013

Re: configure display setting for desktop environment

Hi @mojtaba.ahmadi

 

It seems control signal issue.

Would you make sure sync signal and enable signal by an oscilloscope ?

 

Best regards,

 

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