Questions about fbdriver integration

[Ico Doornekamp <fbdev@zevv.nl>]

Hello,

I have just finished writing a framebuffer driver for a LCD display
connected to our embedded system (monochrome, 128x64, GPIO driven).
It's very similar to the hecubafb driver, and uses deferred IO. I've
included some of the drivers properties at the end of this mail.  Things
works fine when displaying images by doing write()s to /dev/fb0, so this
part seems to be ok.

I hope some of the regulars on this list can clear up some issues
I've run into when using this driver:

- My next step as to redirect the linux console to this framebuffer
  device. I've configured the kernel for framebuffer console, and when
  loading the fbcon module, the message 
    
     Console: switching to mono frame buffer device 16x4" 
     
  appears, and

     cat /sys/class/vtconsole/vtcon1/name -> (M) frame buffer device
     cat /sys/class/vtconsole/vtcon1/bind -> 1
  
  This seems just fine to me, but however, no output appears on the
  display: just a blank screen. 

  It seems that the console is doing *something*, since my driver gets
  triggered by the deferred IO every 200msec (blinking cursor?), problem
  is that the data arriving in my driver is all zeroes!

  So, what would I need to do to get the console working properly with
  my driver ?


- The other question is more a userspace issue: I was hoping to use the
  xorg fbdev server on my dislay, but unfortunately this does not seem
  to support 1 bit depth displays :

    (EE) FBDEV(0): unsupported number of bits per pixel: 1

  Is there a way to make X work on 1-bit fb devices, or am I out of luck
  here ?


Thank you,

Ico


#define DPY_W 128
#define DPY_H 64

static struct fb_fix_screeninfo mbarcfb_fix __devinitdata = {
        .id =           "mbarcfb",
        .type =         FB_TYPE_PACKED_PIXELS,
        .visual =       FB_VISUAL_MONO01,
        .xpanstep =     0,
        .ypanstep =     0,
        .ywrapstep =    0,
        .accel =        FB_ACCEL_NONE,
};

static struct fb_var_screeninfo mbarcfb_var __devinitdata = {
        .xres           = DPY_W,
        .yres           = DPY_H,
        .xres_virtual   = DPY_W,
        .yres_virtual   = DPY_H,
        .bits_per_pixel = 1,
        .nonstd         = 1,
};


-- 
:wq
^X^Cy^K^X^C^C^C^C

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