How to change screen resolution under x-window ?

[SamayaLin]

The environment is MX53 QSB, Linux 2.6.35 from "L2.6.35_11.09.01_ER_source_bundle". The x-window manager under this environment is match-box.

My test procedure are listed below:

A. Prepare for 1080P
    a. Set 1080P in uboot: video=mxcdi0fb:RGB24,1920x1080MR-16@60 hdmi

    b. Get related information by running fbset
        mode "1920x1080-60"
            # D: 138.504 MHz, H: 66.589 kHz, V: 59.936 Hz
            geometry 1920 1080 1920 3240 16
            timings 7220 80 48 3 23 32 5
            hsync high
            rgba 5/11,6/5,5/0,0/0
        endmode

    c. Make set_1080p.sh according to above parameters
        #!/bin/sh
        fbset -g 1920 1080 1920 3240 16 -t 7220 80 48 3 23 32 5 -hsync high

B. Prepare for 720P
    a. Set 72P in uboot: video=mxcdi0fb:RGB24,1280x720MR-16@60 hdmi

    b. Get related information by running fbset
        mode "1280x720-60"
            # D: 64.000 MHz, H: 44.444 kHz, V: 59.979 Hz
            geometry 1280 720 1280 2160 16
            timings 15625 80 48 3 13 32 5
            hsync high
            rgba 5/11,6/5,5/0,0/0
        endmode

    c. Make set_720p.sh according to above parameters
        #!/bin/sh
        fbset -g 1280 720 1280 2160 16 -t 15625 80 48 3 13 32 5

C. fbset test
    a. After boot from uboot 1080P,
        i. I hope the screen resolution can be changed to 720P by executing set_720p.sh, the resolution has been changed, however, the graphics on screen is incorrect. Please refer attachment "set_720P_from_1080P_S.JPG".
        ii. Run set_1080P.sh can restore the screen back to 1080P correctly.

    b. After boot from uboot 720P,
        i. I hope the screen resolution can be changed to 1080P by executing set_1080p.sh, the resolution has been changed, however, the graphics on screen is incorrect. Please refer attachment "set_1080P_from_720P_S.JPG".
        ii. Run set_720P.sh can restore the screen back to 720P correctly.

It seems that fbset can change the screen resolution successfully, but the x-window did not change to new settings.

D. xrandr test

I have tried to use xrandr to change screen resolution according to "http://ubuntuforums.org/showthread.php?t=1112186", however, it seems that the imx graphics driver from freescale did not support xrandr.

# gtf 1280 720 60

 # 1280x720 @ 60.00 Hz (GTF) hsync: 44.76 kHz; pclk: 74.48 MHz
  Modeline "1280x720_60.00"  74.48  1280 1336 1472 1664  720 721 724 746  -HSync +Vsync

 # xrandr --newmode "1280x720_60.00"  74.48  1280 1336 1472 1664  720 721 724 746  -HSync +Vsync

# xrandr --addmode "DISP3 BG" 1280x720_60.00
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  148 (RANDR)
  Minor opcode of failed request:  18 (RRAddOutputMode)
  Serial number of failed request:  20
  Current serial number in output stream:  21

Any suggestion ?

[SamayaLin]

Dear Krishna,

Our application is not running on Ubuntu, I just test xrandr on my Ubuntu desktop environment.

Can you describe more detail? I am not sure the exact procedure of your suggestion. Before writing code to call xrandr libs, I want to make sure the working way on QSB manually.

[KrishnaPavan]

Hi, Samaya Lin,

Set the parameters in the u-boot Board specific files and use xrandr libs available under X11 support in Linux, All this WRT LTIB. Does this work?

Is it that, your application needs only Ubuntu? Because, I think [As I use Linux only] using Linux will help you customise everything more effectively?

I don't know if Ubuntu does the same!

Please Inform..

[SamayaLin]

Setup screen resolution from uboot will take effect, however, we must reboot the system, it's impossible to do it in this way for our application.

I have tried to use xrandr under Ubuntu(on x86 PC, not on QSB), and it can adjust the screen resolution gracefully, so, I think xrandr may be a possible way, but xrandr is failed to work on QSB in my current test.

[KrishnaPavan]

Hi,

Is it possible that the screen resolution has some dependence with the u-boot files?