linux-2.6.5-rc1 vesafb variable refresh rate patch

Zack Winkles winkie at linuxfromscratch.org
Tue Mar 16 20:01:11 PST 2004


Submitted By: Zack Winkles <winkie at linuxfromscratch.org>
Date: 2004-03-16
Initial Package Version: 2.6.5-rc1
Origin: -love patchset (http://www.linuxmall.us/~lovepatch/love-sources)
Description: Enable the use of refresh rates greater than 60 with vesafb.

diff -Naur linux-2.6.5-rc1.orig/arch/i386/boot/vesafb_modes.h linux-2.6.5-rc1/arch/i386/boot/vesafb_modes.h
--- linux-2.6.5-rc1.orig/arch/i386/boot/vesafb_modes.h	1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.5-rc1/arch/i386/boot/vesafb_modes.h	2004-03-16 22:52:42.100123552 -0500
@@ -0,0 +1 @@
+# dummy file
diff -Naur linux-2.6.5-rc1.orig/arch/i386/boot/video.S linux-2.6.5-rc1/arch/i386/boot/video.S
--- linux-2.6.5-rc1.orig/arch/i386/boot/video.S	2004-03-16 00:45:57.000000000 -0500
+++ linux-2.6.5-rc1/arch/i386/boot/video.S	2004-03-16 22:52:42.084125984 -0500
@@ -7,6 +7,8 @@
  *
  *	Rewritten to use GNU 'as' by Chris Noe <stiker at northlink.com> May 1999
  *
+ *	VBE 3.0 refresh rate change code (c) 2003 by Michal 'Spock' Januszewski <spock at o2.pl> 
+ *
  *	For further information, look at Documentation/svga.txt.
  *
  */
@@ -53,6 +55,9 @@
 /* VESA BIOS video modes (VESA number + 0x0200) */
 #define VIDEO_FIRST_VESA 0x0200
 
+/* VESA BIOS video modes with modified refresh rates (VESA number + 0x0400) */
+#define VIDEO_FIRST_VESA_RR 0x0400
+
 /* Video7 special modes (BIOS number + 0x0900) */
 #define VIDEO_FIRST_V7 0x0900
 
@@ -532,13 +537,27 @@
 	movw	-4(%si), %ax			# Fetch mode ID
 	jmp	_m_s
 
+vesa_crtc:
+#include "vesafb_modes.h"
+
 check_vesa:
 	leaw	modelist+1024, %di
-	subb	$VIDEO_FIRST_VESA>>8, %bh
-	movw	%bx, %cx			# Get mode information structure
-	movw	$0x4f01, %ax
+
+#ifdef VIDEO_VESAFB_CRTC_DATA
+	movw	$0x4f00, %ax
+	int     $0x10				# Get VBE Controller information
+
+	cmpw	$0x004f, %ax
+	jnz	setbad
+
+	mov	0x04(%di),%dx			# Save VBE version in DX
+#endif /* VIDEO_VESAFB_CRTC_DATA */
+    
+	movw	%bx, %cx
+	andb	$0b11111001, %ch		# Clear 'special' bits (0x200 & 0x400)
+	movw	$0x4f01, %ax			# Get mode information structure
 	int	$0x10
-	addb	$VIDEO_FIRST_VESA>>8, %bh
+
 	cmpw	$0x004f, %ax
 	jnz	setbad
 
@@ -552,10 +571,76 @@
 	cmpb	$0x99, %al
 	jnz	_setbad				# Doh! No linear frame buffer.
 
-	subb	$VIDEO_FIRST_VESA>>8, %bh
+	andb	$0b11111101, %bh
 	orw	$0x4000, %bx			# Use linear frame buffer
+
 	movw	$0x4f02, %ax			# VESA BIOS mode set call
+
+	cmpb	$0x45, %bh			# 0100 0101 - part of VESA mode number
+	jnz	vesacall				#  |    |
+							# LFB   set if user wants modified refresh rate
+	andb	$0b11111001, %bh
+
+#ifdef VIDEO_VESAFB_CRTC_DATA
+	cmpb	$0x03, %dh			# Do we have VBE 3.0+?
+	jge	_vesa_vbe_ok			# We do..
+
+	leaw	badvbe, %si			# We don't.. 
+	push	%bx
+	push	%ax
+	call	prtstr
+	pop	%ax
+	pop	%bx
+	jmp	vesacall
+
+_vesa_vbe_ok:
+	orb	$0x08, %bh			# Make sure BIOS will use our refresh rates
+	leaw	vesa_crtc, %di
+
+	cmpb	$0x0d, %bl
+	jge	higher_bpp
+
+	addw	$0x003b, %di
+	cmpb	$0x00, %bl			# 640x400 x 256
+	jz	vesacall
+
+	addw	$0x003b, %di
+	cmpb	$0x01, %bl			# 640x480 x 256
+	jz	vesacall
+
+	addw	$0x003b, %di
+	cmpb	$0x03, %bl			# 800x600 x 256/16
+	jle	vesacall
+
+	addw	$0x003b, %di
+	cmpb	$0x05, %bl			# 1024x768 x 256/16
+	jle	vesacall
+	
+	addw	$0x003b, %di
+	jle	vesacall				# 1280x1024 x 256/16
+
+higher_bpp:					# 16, 24, 32bpp
+	cmpb	$0x0f, %bl			# 320x200
+	jle	vesacall
+
+	addw	$0x0076, %di			# skip 640x400
+	cmpb	$0x12, %bl			# 640x480
+	jle	vesacall
+
+	addw	$0x003b, %di
+	cmpb	$0x15, %bl			# 800x600
+	jle	vesacall
+
+	addw	$0x003b, %di
+	cmpb	$0x18, %bl			# 1024x768
+	jle	vesacall
+
+	addw	$0x003b, %di			# 1280x1024
+#endif /* VIDEO_VESAFB_CRTC_DATA */
+
+vesacall:
 	int	$0x10
+
 	cmpw	$0x004f, %ax			# AL=4f if implemented
 	jnz	_setbad				# AH=0 if OK
 
@@ -1948,6 +2033,9 @@
 badmdt:		.ascii	"You passed an undefined mode number."
 		.byte	0x0d, 0x0a, 0
 
+badvbe:		.ascii	"Cannot change refresh rate with VBE < 3.0"
+		.byte	0x0d, 0x0a, 0
+
 vesaer:		.ascii	"Error: Scanning of VESA modes failed. Please "
 		.ascii	"report to <mj at ucw.cz>."
 		.byte	0x0d, 0x0a, 0
diff -Naur linux-2.6.5-rc1.orig/scripts/vesa_modeline_gen.pl linux-2.6.5-rc1/scripts/vesa_modeline_gen.pl
--- linux-2.6.5-rc1.orig/scripts/vesa_modeline_gen.pl	1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.5-rc1/scripts/vesa_modeline_gen.pl	2004-03-16 22:52:42.000000000 -0500
@@ -0,0 +1,150 @@
+#!/usr/bin/perl
+
+# VESAFB Modeline Generator Script v0.2
+# -------------------------------------
+# Author: Michal 'Spock' Januszewski <spock at o2.pl>
+# Last modified: 2003-08-01
+# Distributed under the terms of the GNU General Public License v2
+#
+# Timing calculations based on Colas Nahaboo's XFree86 modeline generator script
+#
+
+# path to the Linux kernel source tree
+$path = "/usr/src/linux";
+$path = `pwd` unless (-d $path);
+
+print "\nVESAFB Modeline Generator Script v0.2\n";
+print "-------------------------------------\n\n";
+print "Note that to achieve best results you might want to make\n";
+print "these values a little lower than your monitor's best.\n\n";
+print "1) Maximal vertical refresh rate [Hz]\n";
+print "   [100]: ";
+
+$ok = 0;
+while (!$ok) {
+    $max_vf = <STDIN>;
+    $max_vf = 100 if ($max_vf =~ /^\s*$/);
+
+    if ($max_vf <= 300 && $max_vf >= 56) {
+        $ok = 1;
+    } else {
+        print "\n\033[1;31mInvalid vertical refresh rate. Please enter a number from range 56 - 300.\033[0;38m\n";
+        print "New value: ";
+    }
+}
+
+print "2) Maximal horizontal refresh rate [kHz]\n";
+print "   [70]: ";
+
+$ok = 0;
+while (!$ok) {
+    $max_hf = <STDIN>;
+    $max_hf = 70 if ($max_hf =~ /^\s*$/);
+
+    if ($max_hf <= 300 && $max_hf >= 30) {
+        $ok = 1;
+    } else {
+        print "\n\033[1;31mInvalid horizontal refresh rate. Please enter a number from range 30 - 300.\033[0;38m\n";
+        print "New value: ";
+    }
+}
+
+print "3) Monitor's maximal bandwidth (aka pixel clock) [MHz]\n";
+print "   [100]: ";
+
+$ok = 0;
+while (!$ok) {
+    $max_bw = <STDIN>;
+    $max_bw = 100 if ($max_bw =~ /^\s*$/);
+
+    if ($max_bw <= 300 && $max_bw >= 30) {
+        $ok = 1;
+    } else {
+        print "\n\033[1;31mInvalid bandwidth. Please enter a number from range 30 - 300.\033[0;38m\n";
+        print "New value: ";
+    }
+}
+
+print "\n";
+
+# (width, height, flags)
+ at res = ((320,200,0x00), (640,400,0x04), (640,480,0x0C), (800,600,0x00), (1024,768,0x00), (1280,1024,0x00));
+
+sub round8 {
+    my $a = shift;
+    $a = (int($a/8)+1)*8;
+    return $a;
+}
+
+sub calc() {
+
+    $d = round8 ($x/24);
+    $x1 = round8 ($x + $d);
+    $x2 = round8 ($x + 6*$d);
+    $hfl = round8 ($x + 8*$d);
+    
+    $y1 = $y+2;
+    $y2 = $y+14;
+    $vfl = $y+40;
+
+    $dcf = $hfl*$vfl*$vf;
+    $bw = $dcf / 1000000;
+    $hsf = $dcf / $hfl / 1000;
+
+    $ok = 0;
+
+}
+
+open MODES,">$path/arch/i386/boot/vesafb_modes.h";
+
+print MODES "# The contents of this file were generated automatically.\n";
+print MODES "# Please do not modify them, unless you are sure what you're doing.\n\n";
+print MODES "# Format:     HorizontalSyncTotal, HorizontalSyncStart, HorizontalSyncEnd\n";
+print MODES "#             VerticalSyncTotal, VerticalSyncStart, VerticalSyndEnd\n";
+print MODES "#             Flags (0 = hsync+, vsync+; 12 = hsync-, vsync-; 8 = hsync-, vsync+, 4 = hsync+, vsync-)\n";
+print MODES "#             Pixel Clock Rate (Hz)\n";
+print MODES "#             Vertical Refresh Rate (in units of 0.01 Hz)\n\n";
+print MODES "#define VIDEO_VESAFB_CRTC_DATA\n\n";
+
+for ($i = 0; $i < $#res; $i += 3) {
+
+    $x = $res[$i];
+    $y = $res[$i+1];
+    $fl = $res[$i+2];
+
+    $vf = $max_vf;
+
+    calc();
+
+    while (!$ok) {
+    
+	$ok = 1;
+
+	if ($hsf > $max_hf) {
+	    $hfl = $dcf / (1000*$max_hf);
+	    $vf = $dcf / ($hfl * $vfl);
+	    calc();
+	}
+
+	if ($bw > $max_bw) {
+	    $dcf = 1000000*$max_bw;
+	    $vf = $dcf / ($hfl * $vfl);
+	    calc();
+	}
+    }
+
+    $vf = int($vf*100);
+
+    print MODES "# ".$x."x".$y." @ ".($vf/100)."Hz\n"; 
+    print MODES "        .word   $hfl, $x1, $x2\n";	# horizontal
+    print MODES "        .word   $vfl, $y2, $y2\n";	# vertical
+    print MODES "        .byte   $fl\n";		# flags
+    print MODES "        .long   $dcf\n";		# pixel clock in Hz
+    print MODES "        .word   $vf\n";		# refresh rate in 0.01 Hz
+    print MODES "        .space  40\n\n";
+
+}
+
+close(MODES);
+
+print "Successfully writen CRTC data for all ".(($#res+1)/3)." predefined VESA resolutions to $path/arch/i386/boot/vesafb_modes.h.\n\n";


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