You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
235 lines
7.7 KiB
235 lines
7.7 KiB
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/framebuffer-howto.doc:36 -->
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
|
<title>Enabling the Linux Framebuffer</title>
|
|
<style type="text/css"><!--
|
|
fn { margin-left: 1cm; text-indent: -1cm; }
|
|
a:link { color: #004faf; text-decoration: none }
|
|
a:visited { color: #672967; text-decoration: none }
|
|
body { background: #ffffff; color: black; }
|
|
--></style>
|
|
</head>
|
|
<body>
|
|
|
|
<table border="0" cellpadding="0" cellspacing="0" width="100%">
|
|
<tr bgcolor="#E5E5E5">
|
|
<td valign=center>
|
|
<a href="index.html">
|
|
<font color="#004faf">Home</font></a>
|
|
| <a href="classes.html">
|
|
<font color="#004faf">All Classes</font></a>
|
|
| <a href="mainclasses.html">
|
|
<font color="#004faf">Main Classes</font></a>
|
|
| <a href="annotated.html">
|
|
<font color="#004faf">Annotated</font></a>
|
|
| <a href="groups.html">
|
|
<font color="#004faf">Grouped Classes</font></a>
|
|
| <a href="functions.html">
|
|
<font color="#004faf">Functions</font></a>
|
|
</td>
|
|
<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Enabling the Linux Framebuffer</h1>
|
|
|
|
|
|
|
|
<p> This is only a short guide.
|
|
See <a href="file:/usr/src/linux/README">/usr/src/linux/README</a> and
|
|
<a href="file:/usr/src/linux/Documentation/fb/">/usr/src/linux/Documentation/fb/</a> for detailed information.
|
|
There is also a detailed explanation at
|
|
<a href="http://www.linuxdoc.org/HOWTO/Framebuffer-HOWTO.html">http://www.linuxdoc.org/HOWTO/Framebuffer-HOWTO.html</a>.
|
|
<p> <ol type=1>
|
|
<li> Make sure that you have the Linux kernel source code in
|
|
<a href="file:/usr/src/linux/">/usr/src/linux/</a>.
|
|
<p> <li> Log in as root and <tt>cd</tt> <tt>/usr/src/linux</tt>
|
|
<p> <li> Configure the kernel:
|
|
<p> Run:
|
|
<pre>
|
|
make menuconfig
|
|
</pre>
|
|
|
|
<p> Select "Code maturity level options" and set "Prompt for
|
|
development and/or incomplete code/drivers".
|
|
<p> Then select "Console drivers" and set "Support for frame buffer
|
|
devices" to built-in (even if it says EXPERIMENTAL). Then configure
|
|
the driver. Most modern graphics cards can use the "VESA VGA
|
|
graphics console"; use that or a driver that specifically matches
|
|
your video card. Finally, enable "Advanced low level driver options"
|
|
and make sure that 16 and 32 bpp packed pixel support are enabled.
|
|
<p> When you are finished, chose exit and save.
|
|
<p> <li> Compile the kernel
|
|
<p> First do:
|
|
<pre>
|
|
make dep
|
|
</pre>
|
|
|
|
then:
|
|
<pre>
|
|
make bzImage
|
|
</pre>
|
|
|
|
<p> The new kernel should now be in arch/i386/boot/bzImage.
|
|
<p> <li> Copy the kernel to the boot directory:
|
|
<pre>
|
|
cp arch/i386/boot/bzImage /boot/linux.vesafb
|
|
</pre>
|
|
|
|
<p> <li> Edit /etc/lilo.conf.
|
|
<p> <b>Warning:</b> Keep a backup of <a href="file:/etc/lilo.conf">/etc/lilo.conf</a>, and have a rescue disk
|
|
available. If you make a mistake, the machine may not boot.
|
|
<p> The file <a href="file:/etc/lilo.conf">/etc/lilo.conf</a> specifies how the system boots. The
|
|
precise contents of the file varies from system to system. Here is
|
|
an example:
|
|
<pre>
|
|
# LILO configuration file
|
|
boot = /dev/hda3
|
|
delay = 30
|
|
image = /boot/vmlinuz
|
|
root = /dev/hda3
|
|
label = Linux
|
|
read-only # Non-UMSDOS filesystems should be mounted read-only for checking
|
|
other=/dev/hda1
|
|
label=nt
|
|
table=/dev/hda
|
|
</pre>
|
|
|
|
<p> Make a new "image" section that is a copy of the first one, but with
|
|
<pre>
|
|
image = /boot/linux.vesafb
|
|
</pre>
|
|
|
|
and
|
|
<pre>
|
|
label = Linux-vesafb
|
|
</pre>
|
|
|
|
Place it just above the first image section.
|
|
<p> Add a line before the image section saying <tt>vga = 791</tt>. (Meaning
|
|
1024x768, 16 bpp.)
|
|
<p> With the above example, lilo.conf would now be:
|
|
<pre>
|
|
# LILO configuration file
|
|
boot = /dev/hda3
|
|
delay = 30
|
|
vga = 791
|
|
image = /boot/linux.vesafb
|
|
root = /dev/hda3
|
|
label = Linux-vesafb
|
|
read-only # Non-UMSDOS filesystems should be mounted read-only for checking
|
|
image = /boot/vmlinuz
|
|
root = /dev/hda3
|
|
label = Linux
|
|
read-only # Non-UMSDOS filesystems should be mounted read-only for checking
|
|
other=/dev/hda1
|
|
label=nt
|
|
table=/dev/hda
|
|
</pre>
|
|
|
|
<p> Do not change any existing lines in the file; just add new ones.
|
|
<p> <li> To make the new changes take effect, run the lilo program:
|
|
<pre>
|
|
lilo
|
|
</pre>
|
|
|
|
<p> <li> Reboot the system. You should now see a penguin logo while the
|
|
system is booting.
|
|
(Or more than one on a multi-processor machine.)
|
|
<p> <li> If it does not boot properly with the new kernel, you can boot with
|
|
the old kernel by entering the label of the old image section at
|
|
the LILO prompt. (with the example lilo.conf file, the old label is
|
|
Linux.)
|
|
<p> If that does not work (probably because of an error in lilo.conf),
|
|
boot the machine using your rescue disk, restore <a href="file:/etc/lilo.conf">/etc/lilo.conf</a> from backup and re-run lilo.
|
|
<p> <li> Testing: Here's a short program that opens the frame buffer and draws a
|
|
gradient-filled red square.
|
|
<p> <pre>
|
|
#include <unistd.h>
|
|
#include <stdio.h>
|
|
#include <fcntl.h>
|
|
#include <linux/fb.h>
|
|
#include <sys/mman.h>
|
|
|
|
int main()
|
|
{
|
|
int fbfd = 0;
|
|
struct fb_var_screeninfo vinfo;
|
|
struct fb_fix_screeninfo finfo;
|
|
long int screensize = 0;
|
|
char *fbp = 0;
|
|
int x = 0, y = 0;
|
|
long int location = 0;
|
|
|
|
// Open the file for reading and writing
|
|
fbfd = open("/dev/fb0", O_RDWR);
|
|
if (!fbfd) {
|
|
printf("Error: cannot open framebuffer device.\n");
|
|
exit(1);
|
|
}
|
|
printf("The framebuffer device was opened successfully.\n");
|
|
|
|
// Get fixed screen information
|
|
if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
|
|
printf("Error reading fixed information.\n");
|
|
exit(2);
|
|
}
|
|
|
|
// Get variable screen information
|
|
if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
|
|
printf("Error reading variable information.\n");
|
|
exit(3);
|
|
}
|
|
|
|
printf("%dx%d, %dbpp\n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel );
|
|
|
|
// Figure out the size of the screen in bytes
|
|
screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;
|
|
|
|
// Map the device to memory
|
|
fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED,
|
|
fbfd, 0);
|
|
if ((int)fbp == -1) {
|
|
printf("Error: failed to map framebuffer device to memory.\n");
|
|
exit(4);
|
|
}
|
|
printf("The framebuffer device was mapped to memory successfully.\n");
|
|
|
|
x = 100; y = 100; // Where we are going to put the pixel
|
|
|
|
// Figure out where in memory to put the pixel
|
|
for ( y = 100; y < 300; y++ )
|
|
for ( x = 100; x < 300; x++ ) {
|
|
|
|
location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +
|
|
(y+vinfo.yoffset) * finfo.line_length;
|
|
|
|
if ( vinfo.bits_per_pixel == 32 ) {
|
|
*(fbp + location) = 100; // Some blue
|
|
*(fbp + location + 1) = 15+(x-100)/2; // A little green
|
|
*(fbp + location + 2) = 200-(y-100)/5; // A lot of red
|
|
*(fbp + location + 3) = 0; // No transparency
|
|
} else { //assume 16bpp
|
|
int b = 10;
|
|
int g = (x-100)/6; // A little green
|
|
int r = 31-(y-100)/16; // A lot of red
|
|
unsigned short int t = r<<11 | g << 5 | b;
|
|
*((unsigned short int*)(fbp + location)) = t;
|
|
}
|
|
|
|
}
|
|
munmap(fbp, screensize);
|
|
close(fbfd);
|
|
return 0;
|
|
}
|
|
</pre>
|
|
|
|
</ol>
|
|
<p>
|
|
<!-- eof -->
|
|
<p><address><hr><div align=center>
|
|
<table width=100% cellspacing=0 border=0><tr>
|
|
<td>Copyright © 2007
|
|
<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
|
|
<td align=right><div align=right>TQt 3.3.8</div>
|
|
</table></div></address></body>
|
|
</html>
|