lcd4linux-users

[lcd4linux] add to Compiling on 2.4 kernels and a question =D

[Ralph J. <pen...@ca...>]

hi just read all the posts i got one thing to add for anyone that might
possibly be trying to compile for 2.4 kernels, especially on RedHat
distribution.
 
    the install of the kernel-sources rpm is somwhat broken. there is a
directory in /usr/include named asm. libraries for assembly if i am not
mistaken. however the directory is missing some header files. the best
way to resolve this and not recieve errors due to a "missing msr.h file"
is by creating a symlink to the correct directory which is found in
/usr/src this helped me:
 
        mv /usr/include/asm /usr/include/asm.old
        ln -s /usr/src/linux-2.4.18-14/include/asm-i386 /usr/include/asm
 
I actually came across the resolution on a RedHat bulletin board. it
seems that for some reason they didnt add all the correct files into
/usr/include
 
Then proceed with make. be advised: in my case the directory was name
asm-i386 because that is my architecture. depending on what you are
running that directory may be different. just check out your own sources
directory. i'm telling you once i did that, boom boom, it compiled
beautifully and i had the thing up and running in less than 5 minutes.
 
I have a quick question, i did see in one post that scrolling is not yet
supported, i believe thats what i understood. However, is it possible to
create multiple screens, that are displayed at given intervals? I did
see a post about this but it was never answered. Also I did notice that
some of the new CrystalFontz LCDs do have inherent scrolling
capabilities, does this mean that if i send to it multiple lines it will
scroll on its own? I just havent tested it out for myself because i
havent yet bought an LCD, i've just been messing around with the X11
driver, which i think is excellent. Any help with this would be greatly
appreciated. thanks!
 
Ralph Jaquez
Mainframe Systems Support

Re: [lcd4linux] add to Compiling on 2.4 kernels and a question =D

[Michael R. <re...@eu...>]

Hi Ralph,

[...]

>         mv /usr/include/asm /usr/include/asm.old
>         ln -s /usr/src/linux-2.4.18-14/include/asm-i386 /usr/include/asm
[...]
> Then proceed with make. be advised: in my case the directory was name 
> asm-i386 because that is my architecture. depending on what you are 
> running that directory may be different. just check out your own sources 
> directory. i'm telling you once i did that, boom boom, it compiled 
> beautifully and i had the thing up and running in less than 5 minutes.

Well, this has been fixed some time ago, but only in the CVS version. At 
the moment lcd4linux gehaves that way, if msr.h cannot be found, only 
the gettimeofday() delay loop will be used. But I will change this 
again, hard-coding the only small definition needed from msr.h into 
udelay.c:

#define rdtscl(low) \
      __asm__ __volatile__("rdtsc" : "=a" (low) : : "edx")

This may break architectures which doe not have an rdtsc command, but 
this should be checked during the parse of /proc/cpuinfo.

> I have a quick question, i did see in one post that scrolling is not yet 
> supported, i believe thats what i understood. However, is it possible to 
> create multiple screens, that are displayed at given intervals? I did 
> see a post about this but it was never answered. Also I did notice that 
> some of the new CrystalFontz LCDs do have inherent scrolling 
> capabilities, does this mean that if i send to it multiple lines it will 
> scroll on its own? I just havent tested it out for myself because i 
> havent yet bought an LCD, i've just been messing around with the X11 
> driver, which i think is excellent. Any help with this would be greatly 
> appreciated. thanks!

You're right, scrolling or havind multiple screens is not supported at 
the moment.

There's one workaround: you can provide several config files, and have a 
shellscript which periodically rotates a symlink over your 
configurations, and sends a SIGHUP to the lcd4linux process (which 
forces kind of a "restart", including re-read of the config file.)

At the moment I'm waiting for some test results of the Cwlinux driver, 
and will release 0.99 (or 0.9.9, I'm changing the numbering scheme) 
hopefully shortly. After that I'm thinking about a redesign, 
implementing a client-server modell (similar to lcdproc), but not on a 
"screen" basis, but based on windows and widgets (so one screen can 
display information from different clients).


bye, Michael

-- 
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Michael Reinelt                                   Fax: +43 316  692343
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