Discussion

DirectFB on 3'5 RGB screen

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Edited by destroyedlolo at Mon Feb 16, 2015 23:35

Hello,

Does someone tried to use DirectFB with a 3'5 screen ?

If so, any tips ? Which option did you use on your kernet etc ...

Thanks
So, nobody played with frame buffer ?

sigmoid  
I intend to do that once I can get my hand on one of those screens, so let's sync up. In the meantime, let me ask you where did you buy yours? ;)

Which OS are your running ? On my side, it will be Gentoo.
I already checked that the mali driver is present on my kernel, but didn't go further as I have other tasks before on my todo list (basement server upgrade - done, finalization of remote sound playing - 75%, and upgrade of BananaLEDd for bPRO, ...) and my free time is vampired by the ski

sigmoid  
I'm still in the process of ordering mine, but here's a blogpost I found about setting it up:
[http://hardware-libre.fr/2015/02 ... uch-display-module/]

Well ok, I did some tests this evening.
* I modified the fex as per the one provided by LeMaker.
* loaded lcd mali mali_drm kernel modules but ... nothing after reboot. I think I'm missing a kernel module or something to redirect the console to this screen (or perhaps it's because I don't have a keyboard connected) as I have only the 2 penguins with the default fex and my bPI connect thru HDMI. But this time, screen off

Well, ok, stupid I am : I did connect the screen on the sci connector instead of the screen one

Working perfectly now.

I did some llllooonnngggg searches but without success

I did an installation of the Gentoo/upstream DirectFB but it's creating only a dummy screen :
  1.    ~~~~~~~~~~~~~~~~~~~~~~~~~~| DirectFB 1.4.9 |~~~~~~~~~~~~~~~~~~~~~~~~~~
  2.         (c) 2001-2010  The world wide DirectFB Open Source Community
  3.         (c) 2000-2004  Convergence (integrated media) GmbH
  4.       ----------------------------------------------------------------

  5. (*) DirectFB/Core: Single Application Core. (2015-03-10 21:27)
  6. (*) Direct/Memcpy: Using libc memcpy()
  7. (*) Direct/Thread: Started 'Linux Input' (-1) [INPUT OTHER/OTHER 0/0] <8388608>...
  8. (*) DirectFB/Input: sunxi-ir (1) 0.1 (directfb.org)
  9. (*) Direct/Thread: Started 'Linux Input' (-1) [INPUT OTHER/OTHER 0/0] <8388608>...
  10. (*) DirectFB/Input: axp20-supplyer (2) 0.1 (directfb.org)
  11. (*) Direct/Thread: Started 'Hotplug with Linux Input' (-1) [INPUT OTHER/OTHER 0/0] <8388608>...
  12. (*) DirectFB/Input: Hot-plug detection enabled with Linux Input Driver
  13. (*) DirectFB/Graphics: Generic Software Rasterizer 0.6 (directfb.org)
  14. (*) DirectFB/Core/WM: Default 0.3 (directfb.org)


  15. Screen (00) Dummy                           (primary screen)
  16.    Caps:

  17.      Layer (00) Dummy                           (primary layer)
  18.         Type:    GRAPHICS
  19.         Caps:    SURFACE


  20. Input (00) sunxi-ir                        (primary keyboard)
  21.    Type: KEYBOARD
  22.    Caps: KEYS
  23.    Min. Keycode: 0
  24.    Max. Keycode: 127

  25. Input (10) axp20-supplyer               
  26.    Type:
  27.    Caps: KEYS
  28.    Min. Keycode: -1
  29.    Max. Keycode: -1
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I think it's because it don't know mali driver. I found some stuffs here : http://linux-sunxi.org/Buildroot
but for me, it's a bit wried if I have to build a full BSP for a foreign card only to got this DirectDB lib.

Does someone knowing a better procedure ?

Edited by destroyedlolo at Wed Mar 11, 2015 22:30

Ok, working

  • load lcd mali mali_drm kernel module which creates /dev/fb0
  • compile DirectFB with fbcon option. truetype, gif, png can help also to compile directfb's example, and voila ...

Edited by destroyedlolo at Sat Apr 11, 2015 22:04

Well, did someone succeeded to disable the backlight ?

As per the FEX file, it should be driven by
  1. lcd_bl_en = port:PH08<1><0><default><1>
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which is linked to GPIO 56

But I can't drive the backlight :
  1. cd /sys/class/gpio/
  2. echo 56 > export
  3. cd gpio56/
  4. echo out > direction
  5. echo 0 > value
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don't do anything

As per the same FEX file, the LCD pwm is driven by
  1. port:PB02<2><0><default><default>
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so GPIO 57
And this time is worked ... but only to switch the display on and off.
As it's labeled PWM, it is possible to change the light intensity ?

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