root/drivers/char/vesa_blank.c

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DEFINITIONS

This source file includes following definitions.
  1. vesa_blank
  2. vesa_unblank
  3. set_vesa_blanking

   1 /*
   2  * vesa_blank.c
   3  *
   4  * Exported functions:
   5  *      void vesa_blank(void);
   6  *      void vesa_unblank(void);
   7  *      void set_vesa_blanking(const unsigned long arg);
   8  *
   9  * Not all hardware reacts well to this code - activate at your own risk.
  10  * Activation is done using a sufficiently recent version of setterm
  11  * or using a tiny C program like the following.
  12  *
  13 -----------------------------------------------------------------------
  14 |#include <stdio.h>
  15 |#include <linux/termios.h>
  16 |main(int argc, char *argv[]) {
  17 |    int fd;
  18 |    struct { char ten, onoff; } arg;
  19 |
  20 |    if (argc != 2) {
  21 |       fprintf(stderr, "usage: setvesablank ON|on|off\n");
  22 |       exit(1);
  23 |    }
  24 |    if ((fd = open("/dev/console", 0)) < 0)
  25 |      fd = 0;
  26 |    arg.ten = 10;
  27 |    arg.onoff = 0;
  28 |    if (!strcmp(argv[1], "on"))
  29 |      arg.onoff = 1;
  30 |    else if (!strcmp(argv[1], "ON"))
  31 |      arg.onoff = 2;
  32 |    if (ioctl(fd, TIOCLINUX, &arg)) {
  33 |       perror("setvesablank: TIOCLINUX");
  34 |       exit(1);
  35 |    }
  36 |    exit(0);
  37 |}
  38 -----------------------------------------------------------------------
  39 */
  40 
  41 #include <asm/io.h>
  42 #include <asm/system.h>
  43 extern unsigned short video_port_reg, video_port_val;
  44 
  45 /*
  46  * This file handles the VESA Power Saving Protocol that lets a
  47  * monitor be powered down whenever not needed for a longer time.
  48  * The VESA protocol defines:
  49  *
  50  *  Mode/Status         HSync   VSync   Video
  51  *  -------------------------------------------
  52  *  "On"                on      on      active  (mode 0)
  53  *  "Suspend" {either}  on      off     blank   (mode 1)
  54  *            {  or  }  off     on      blank   
  55  *  "Off"               off     off     blank   (mode 2)
  56  *
  57  * Original code taken from the Power Management Utility (PMU) of
  58  * Huang shi chao, delivered together with many new monitor models
  59  * capable of the VESA Power Saving Protocol.
  60  *
  61  * Adapted to Linux by Christoph Rimek (chrimek@toppoint.de)  15-may-94.
  62  * A slightly adapted fragment of his README follows.
  63  *
  64 Patch (based on Linux Kernel revision 1.0) for handling the Power Saving
  65 feature of the new monitor generation. The code works on all these monitors
  66 (mine is a Smile 1506) and should run on *all* video adapter cards (change
  67 some i/o-adresses), although tested only on two different VGA-cards: a  
  68 cheap Cirrus Logic (5428) and a miro Crystal 8S (S3-805).
  69 
  70 You can choose from two options:
  71 
  72 (1) Setting vesa_blanking_mode to 1.
  73     The code will save the current setting of your video adapters'
  74     register settings and then program the controller to turn off
  75     the vertical synchronisation pulse.
  76 
  77 (2) Setting vesa_blanking_mode to 2.
  78     If your monitor locally has an Off_Mode timer then you should not
  79     force your video card to send the OFF-signal - your monitor will
  80     power down by itself.
  81     If your monitor cannot handle this and needs the Off-signal directly,
  82     or if you like your monitor to power down immediately when the
  83     blank_timer times out, then you choose this option.
  84 
  85 On the other hand I'd recommend to not choose this second option unless
  86 it is absolutely necessary. Powering down a monitor to the Off_State with
  87 an approx. power consumption of 3-5 Watts is a rather strong action for
  88 the CRT and it should not be done every now and then. If the software only  
  89 sends the signal to enter Standby mode, you have the chance to interfere
  90 before the monitor powers down. Do not set a too short period, if you love
  91 your hardware :-)) .
  92 
  93 If requested, in the future it may be possible to install another timer
  94 to provide a configurable delay between the two stages Standby and Off
  95 similar to the "setterm -blank"-feature.
  96 */
  97 
  98 #define seq_port_reg    (0x3c4)         /* Sequencer register select port */
  99 #define seq_port_val    (0x3c5)         /* Sequencer register value port  */
 100 #define video_misc_rd   (0x3cc)         /* Video misc. read port          */
 101 #define video_misc_wr   (0x3c2)         /* Video misc. write port         */
 102 
 103 /* structure holding original VGA register settings */
 104 static struct {
 105         unsigned char   SeqCtrlIndex;           /* Sequencer Index reg.   */
 106         unsigned char   CrtCtrlIndex;           /* CRT-Contr. Index reg.  */
 107         unsigned char   CrtMiscIO;              /* Miscellaneous register */
 108         unsigned char   HorizontalTotal;        /* CRT-Controller:00h */
 109         unsigned char   HorizDisplayEnd;        /* CRT-Controller:01h */
 110         unsigned char   StartHorizRetrace;      /* CRT-Controller:04h */
 111         unsigned char   EndHorizRetrace;        /* CRT-Controller:05h */
 112         unsigned char   Overflow;               /* CRT-Controller:07h */
 113         unsigned char   StartVertRetrace;       /* CRT-Controller:10h */
 114         unsigned char   EndVertRetrace;         /* CRT-Controller:11h */
 115         unsigned char   ModeControl;            /* CRT-Controller:17h */
 116         unsigned char   ClockingMode;           /* Seq-Controller:01h */
 117 } vga;
 118 
 119 static int vesa_blanking_mode = 0;
 120 static int vesa_blanked = 0;
 121 
 122 /* routine to blank a vesa screen */
 123 void vesa_blank(void)
     /* [previous][next][first][last][top][bottom][index][help] */
 124 {
 125         int mode;
 126 
 127         if((mode = vesa_blanking_mode) == 0)
 128           return;
 129 
 130         /* save original values of VGA controller registers */
 131         cli();
 132         vga.SeqCtrlIndex = inb_p(seq_port_reg);
 133         vga.CrtCtrlIndex = inb_p(video_port_reg);
 134         vga.CrtMiscIO = inb_p(video_misc_rd);
 135         sti();
 136 
 137         if(mode == 2) {
 138             outb_p(0x00,video_port_reg);                /* HorizontalTotal */
 139             vga.HorizontalTotal = inb_p(video_port_val);
 140             outb_p(0x01,video_port_reg);                /* HorizDisplayEnd */
 141             vga.HorizDisplayEnd = inb_p(video_port_val);
 142             outb_p(0x04,video_port_reg);                /* StartHorizRetrace */
 143             vga.StartHorizRetrace = inb_p(video_port_val);
 144             outb_p(0x05,video_port_reg);                /* EndHorizRetrace */
 145             vga.EndHorizRetrace = inb_p(video_port_val);
 146         }
 147         outb_p(0x07,video_port_reg);                    /* Overflow */
 148         vga.Overflow = inb_p(video_port_val);
 149         outb_p(0x10,video_port_reg);                    /* StartVertRetrace */
 150         vga.StartVertRetrace = inb_p(video_port_val);
 151         outb_p(0x11,video_port_reg);                    /* EndVertRetrace */
 152         vga.EndVertRetrace = inb_p(video_port_val);
 153         outb_p(0x17,video_port_reg);                    /* ModeControl */
 154         vga.ModeControl = inb_p(video_port_val);
 155         outb_p(0x01,seq_port_reg);                      /* ClockingMode */
 156         vga.ClockingMode = inb_p(seq_port_val);
 157 
 158         /* assure that video is enabled */
 159         /* "0x20" is VIDEO_ENABLE_bit in register 01 of sequencer */
 160         cli();
 161         outb_p(0x01,seq_port_reg);
 162         outb_p(vga.ClockingMode | 0x20,seq_port_val);
 163 
 164         /* test for vertical retrace in process.... */
 165         if ((vga.CrtMiscIO & 0x80) == 0x80)
 166                 outb_p(vga.CrtMiscIO & 0xef,video_misc_wr);
 167 
 168         /*
 169          * Set <End of vertical retrace> to minimum (0) and
 170          * <Start of vertical Retrace> to maximum (incl. overflow)
 171          * Result: turn off vertical sync (VSync) pulse.
 172          */
 173         outb_p(0x10,video_port_reg);            /* StartVertRetrace */
 174         outb_p(0xff,video_port_val);            /* maximum value */
 175         outb_p(0x11,video_port_reg);            /* EndVertRetrace */
 176         outb_p(0x40,video_port_val);            /* minimum (bits 0..3)  */
 177         outb_p(0x07,video_port_reg);            /* Overflow */
 178         outb_p(vga.Overflow | 0x84,video_port_val);     /* bits 9,10 of  */
 179                                                         /* vert. retrace */
 180         if (mode == 2) {
 181             /*
 182              * Set <End of horizontal retrace> to minimum (0) and
 183              *  <Start of horizontal Retrace> to maximum
 184              * Result: turn off horizontal sync (HSync) pulse.
 185              */
 186             outb_p(0x04,video_port_reg);        /* StartHorizRetrace */
 187             outb_p(0xff,video_port_val);        /* maximum */
 188             outb_p(0x05,video_port_reg);        /* EndHorizRetrace */
 189             outb_p(0x00,video_port_val);        /* minimum (0) */
 190         }
 191 
 192         /* restore both index registers */
 193         outb_p(vga.SeqCtrlIndex,seq_port_reg);
 194         outb_p(vga.CrtCtrlIndex,video_port_reg);
 195         sti();
 196 
 197         vesa_blanked = mode;
 198 }       
 199 
 200 /* routine to unblank a vesa screen */
 201 void vesa_unblank(void)
     /* [previous][next][first][last][top][bottom][index][help] */
 202 {
 203         if (!vesa_blanked)
 204           return;
 205 
 206         /* restore original values of VGA controller registers */
 207         cli();
 208         outb_p(vga.CrtMiscIO,video_misc_wr);
 209 
 210         if (vesa_blanked == 2) {
 211             outb_p(0x00,video_port_reg);        /* HorizontalTotal */
 212             outb_p(vga.HorizontalTotal,video_port_val);
 213             outb_p(0x01,video_port_reg);        /* HorizDisplayEnd */
 214             outb_p(vga.HorizDisplayEnd,video_port_val);
 215             outb_p(0x04,video_port_reg);        /* StartHorizRetrace */
 216             outb_p(vga.StartHorizRetrace,video_port_val);
 217             outb_p(0x05,video_port_reg);        /* EndHorizRetrace */
 218             outb_p(vga.EndHorizRetrace,video_port_val);
 219         }
 220         outb_p(0x07,video_port_reg);            /* Overflow */
 221         outb_p(vga.Overflow,video_port_val);
 222         outb_p(0x10,video_port_reg);            /* StartVertRetrace */
 223         outb_p(vga.StartVertRetrace,video_port_val);
 224         outb_p(0x11,video_port_reg);            /* EndVertRetrace */
 225         outb_p(vga.EndVertRetrace,video_port_val);
 226         outb_p(0x17,video_port_reg);            /* ModeControl */
 227         outb_p(vga.ModeControl,video_port_val);
 228         outb_p(0x01,seq_port_reg);              /* ClockingMode */
 229         outb_p(vga.ClockingMode,seq_port_val);
 230 
 231         /* restore index/control registers */
 232         outb_p(vga.SeqCtrlIndex,seq_port_reg);
 233         outb_p(vga.CrtCtrlIndex,video_port_reg);
 234         sti();
 235 
 236         vesa_blanked = 0;
 237 }
 238 
 239 void set_vesa_blanking(const unsigned long arg) {
     /* [previous][next][first][last][top][bottom][index][help] */
 240         char *argp = (char *)(arg + 1);
 241         unsigned int mode = get_fs_byte(argp);
 242         vesa_blanking_mode = ((mode < 3) ? mode : 0);
 243 }

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