Qs: Kernel memory allocation; fbcon greyscale implementation

Timo Ketola (timo.ketola@epec.fi)
Thu, 22 Apr 1999 08:20:07 +0000


Hi folks,

I'm sorry if these are too trivial - but...

I have put Linux 2.2.5 into a nonstandard ix86 hardware (AMD Elan) -
that is there is no BIOS, no VGA but an LCD display...
Its working now but 3 questions arose:

1) Display hardware needs a memory block for it's frame buffer from the
main ram aligned to a 64K boundary. How do I best allocate this. Now I
reduced the memory size reported to the kernel and ioremap'ped the top
memory block into the virtual memory. But as this is not in control of
the driver I think its not the correct way.

2) The kernel message says that 412k of the memory is reserved. I'm
afraid that the 640k-1M area is reserved and lost. If thats true, how
can I get them back.

3) The display is 16 level gray scale, 4 bpp, 2 pixels in a byte. In
what visual type does it map nicely. It seems to me that the fbcon
treats it as a pseudocolor device. At least the appearing logo is
indexed color picture - I think. I don't have very clear idea how this
affects for example the applications. I think I saw a note somewhere
about this kind of display but from the sources I don't get the idea how
it shoulf be implemented.

Thanks in advance!

BTW, this is my first posting here so excuse me for any failures to
follow the netiquette. And, of course, I don't mind being pointed to
FAQs, docs or correct lists.

--
Timo

--

Epec Oy Timo Ketola Box 194 FIN-60101 Seinäjoki

timo.ketola@epec.fi

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