framebuffer questions

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Hi All,


i have to connect an ARM-board to a LC-Display. Its a graphical display with
a resolution of 120x64 Pixel. The ARM-Board has a VGA-Chip onboard. The
customer wants to use X for this display, whatever reason he will have. So
my question is now: what is the best way to bring these things together?
Should i adapt the kernel-fbdev or the fbdevhw from X? Or is there an
easier way? Is there someone who has made such development and will share
his Experiences? Thank you,

regards, Jens  

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Re: framebuffer questions
Jens Nixdorf schrubte am Dienstag, 19. August 2003 11:28:
 
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Some corrections: The board _has_ VGA, but the display ist connected through
the data-bus of the processor, so i cannot use VGA.

regards, Jens
 

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Re: framebuffer questions

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I don't think that you're going to be able to plug the LCD into the
VGA.  Most smaller displays like that aren't setup for that

Assuming that you can't, you're going to have to write a driver.  

You can

1) Write a driver for XFree86
2) Write a kernel framebuffer driver, and use the X framebuffer server

However, I have no idea how well Linux will function with a non-VGA
size screen.

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Re: framebuffer questions
Alex Pavloff schrubte am Mittwoch, 20. August 2003 17:44:

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You're right, the lcd will be connected to a cpu-port.

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To write a driver is also my idea. So i looked into the kernel-sources to
get some understanding how the framebuffer works. But there are some things
i didn't found out yet:

1. The framebuffer represents mostly the memory of a vga-card, but i need
also the write-routines, because i have to change the port to write to.
Where is this set in the kernel? Or should i put my own write-routines
directly into the framebuffer (fbmem.c)?

2. Normally there are several fb-drivers in the source. When they are
compiled as modules, the kernel looks at the hardware, is reading some
stuff and with this stuff it can determine which card is connected. My lcd
is deaf and mutely, because the lack of own "intelligence", so it would not
answer. How can i say the kernel, that it has to use _my_
framebuffer-driver?

Screen sizes shouldnt be a problem, because the customers product will be a
handheld-like device, which has only predefined applications on it (which
also have to be written yet).

regards, Jens

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Re: framebuffer questions

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There are various kernel command line options that will work.

For these questions that I can't answer properly , I would really
recommend asking the folks on the linux fb list...

https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel
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