Mercurial > sdl-ios-xcode
view src/cdrom/openbsd/SDL_syscdrom.c @ 4139:568c9b3c0167 SDL-1.2
* Added configure option --enable-screensaver, to allow enabling the screensaver by default.
* Use XResetScreenSaver() instead of disabling screensaver entirely.
Full discussion summary from Erik on the SDL mailing list:
Current behaviour
=================
SDL changes the user's display power management settings without
permission from the user and without telling the user.
The interface that it uses to do so is DPMSDisable/DPMSEnable, which
should only ever be used by configuration utilities like KControl, never
by normal application programs, let alone by the libraries that they
use. Using an interface that is not at all intended for what SDL tries
to achieve means that it will not work as it should. Firstly, the power
management is completely disabled during the whole lifetime of the SDL
program, not only when it should be. Secondly, it makes SDL
non-reentrant, meaning that things will break when multiple SDL programs
are clients of the same X server simultaneously. Thirdly, no cleanup
mechanism ensures that the setting is restored if the client does not do
that (for example if it crashes).
In addition to that, this interface is broken on xorg,
[http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries
to do does not work at all on that implementation of the X Window
System. (The reason that the DPMSEnable works in KControl is that it
calls DPMSSetTimeout immediately after,
[http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]).
The problems that the current behaviour causes
==============================================
1. Information leak. When the user is away, someone might see what the
user has on the display when the user counts on the screensaver
preventing this. This does not even require physical access to the
workstation, it is enough to see it from a distance.
2. Draining battery. An SDL program that runs on a laptop will quickly
drain the battery while the user is away. The system will soon shut down
and require recharging before being usable again, while it should in
fact have consumed very little energy if the user's settings would have
been obeyed.
3. Wasting energy. Even if battery issues are not considered, energy as
such is wasted.
4. Display wear. The display may be worn out.
The problems that the current behaviour tries to solve
======================================================
1. Preventing screensaver while playing movies.
Many SDL applications are media players. They have reasons to prevent
screensavers from being activated while a movie is being played. When a
user clicks on the play button it can be interpreted as saying "play
this movie, but do not turn off the display while playing it, because I
will watch it even though I do not interact with the system".
2. Preventing screensaver when some input bypasses X.
Sometimes SDL uses input from another source than the X server, so
that the X server is bypassed. This obviously breaks the screensaver
handling. SDL tries to work around that.
3. Preventing screensaver when all input bypasses X.
There is something called Direct Graphics Access mode, where a
program takes control of both the display and the input devices from the
X server. This obviously means that the X server can not handle the
screensaver alone, since screensaver handling depends on input handling.
SDL does not do what it should to help the X server to handle the
screensaver. Nor does SDL take care of screeensaver handling itself. SDL
simply disables the screensaver completely.
How the problems should be solved
=================================
The correct way for an application program to prevent the screensaver
under X is to call XResetScreenSaver. This was recently discovered and
implemented by the mplayer developers,
[http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to
wrap this in an API call (SDL_ResetScreenSaver) and implement it for the
other video targets (if they do not have a corresponding call, SDL
should do what it takes on that particular target, for example sending
fake key events).
1. When a movie is played, the player should reset the screensaver when
the animation is advanced to a new frame. The same applies to anything
similar, like slideshows.
2. When the X server is handling input, it must handle all input
(keyboards, mice, gamepads, ...). This is necessary, not only to be able
to handle the screensaver, but also so that it can send the events to
the correct (the currently active) client. If there is an input device
that the X server can not handle for some reason (such as lack of Plug
and Play capability), the program that handles the device as a
workaround must simulate what would happen if the X server would have
handled the device, by calling XResetScreenSaver when input is received
from the device.
3. When the X server is not handling the input, it depends on the
program that does to call XResetScreenSaver whenever an input event
occurs. Alternatively the program must handle the screensaver countdown
internally and call XActivateScreenSaver.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 29 Feb 2008 13:55:44 +0000 |
parents | 92947e3a18db |
children | 782fd950bd46 c121d94672cb a1b03ba2fcd0 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2006 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Sam Lantinga slouken@libsdl.org */ #include "SDL_config.h" #ifdef SDL_CDROM_OPENBSD /* Functions for system-level CD-ROM audio control */ #include <sys/types.h> #include <sys/ioctl.h> #include <sys/stat.h> #include <fcntl.h> #include <errno.h> #include <unistd.h> #include <sys/ioctl.h> #include <sys/cdio.h> #include "SDL_cdrom.h" #include "../SDL_syscdrom.h" /* The maximum number of CD-ROM drives we'll detect */ #define MAX_DRIVES 16 /* A list of available CD-ROM drives */ static char *SDL_cdlist[MAX_DRIVES]; static dev_t SDL_cdmode[MAX_DRIVES]; /* The system-dependent CD control functions */ static const char *SDL_SYS_CDName(int drive); static int SDL_SYS_CDOpen(int drive); static int SDL_SYS_CDGetTOC(SDL_CD *cdrom); static CDstatus SDL_SYS_CDStatus(SDL_CD *cdrom, int *position); static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length); static int SDL_SYS_CDPause(SDL_CD *cdrom); static int SDL_SYS_CDResume(SDL_CD *cdrom); static int SDL_SYS_CDStop(SDL_CD *cdrom); static int SDL_SYS_CDEject(SDL_CD *cdrom); static void SDL_SYS_CDClose(SDL_CD *cdrom); /* Some ioctl() errno values which occur when the tray is empty */ #define ERRNO_TRAYEMPTY(errno) \ ((errno == EIO) || (errno == ENOENT) || (errno == EINVAL) || \ (errno == ENODEV)) /* Check a drive to see if it is a CD-ROM */ static int CheckDrive(char *drive, struct stat *stbuf) { int is_cd, cdfd; struct ioc_read_subchannel info; /* If it doesn't exist, return -1 */ if ( stat(drive, stbuf) < 0 ) { return(-1); } /* If it does exist, verify that it's an available CD-ROM */ is_cd = 0; if ( S_ISCHR(stbuf->st_mode) || S_ISBLK(stbuf->st_mode) ) { cdfd = open(drive, (O_RDONLY|O_EXCL|O_NONBLOCK), 0); if ( cdfd >= 0 ) { info.address_format = CD_MSF_FORMAT; info.data_format = CD_CURRENT_POSITION; info.data_len = 0; info.data = NULL; /* Under Linux, EIO occurs when a disk is not present. This isn't 100% reliable, so we use the USE_MNTENT code above instead. */ if ( (ioctl(cdfd, CDIOCREADSUBCHANNEL, &info) == 0) || ERRNO_TRAYEMPTY(errno) ) { is_cd = 1; } close(cdfd); } else if (ERRNO_TRAYEMPTY(errno)) is_cd = 1; } return(is_cd); } /* Add a CD-ROM drive to our list of valid drives */ static void AddDrive(char *drive, struct stat *stbuf) { int i; if ( SDL_numcds < MAX_DRIVES ) { /* Check to make sure it's not already in our list. This can happen when we see a drive via symbolic link. */ for ( i=0; i<SDL_numcds; ++i ) { if ( stbuf->st_rdev == SDL_cdmode[i] ) { #ifdef DEBUG_CDROM fprintf(stderr, "Duplicate drive detected: %s == %s\n", drive, SDL_cdlist[i]); #endif return; } } /* Add this drive to our list */ i = SDL_numcds; SDL_cdlist[i] = SDL_strdup(drive); if ( SDL_cdlist[i] == NULL ) { SDL_OutOfMemory(); return; } SDL_cdmode[i] = stbuf->st_rdev; ++SDL_numcds; #ifdef DEBUG_CDROM fprintf(stderr, "Added CD-ROM drive: %s\n", drive); #endif } } int SDL_SYS_CDInit(void) { static char *checklist[] = { #if defined(__OPENBSD__) "?0 cd?c", "cdrom", NULL #elif defined(__NETBSD__) "?0 cd?d", "?0 cd?c", "cdrom", NULL #else "?0 cd?c", "?0 acd?c", "cdrom", NULL #endif }; char *SDLcdrom; int i, j, exists; char drive[32]; struct stat stbuf; /* Fill in our driver capabilities */ SDL_CDcaps.Name = SDL_SYS_CDName; SDL_CDcaps.Open = SDL_SYS_CDOpen; SDL_CDcaps.GetTOC = SDL_SYS_CDGetTOC; SDL_CDcaps.Status = SDL_SYS_CDStatus; SDL_CDcaps.Play = SDL_SYS_CDPlay; SDL_CDcaps.Pause = SDL_SYS_CDPause; SDL_CDcaps.Resume = SDL_SYS_CDResume; SDL_CDcaps.Stop = SDL_SYS_CDStop; SDL_CDcaps.Eject = SDL_SYS_CDEject; SDL_CDcaps.Close = SDL_SYS_CDClose; /* Look in the environment for our CD-ROM drive list */ SDLcdrom = SDL_getenv("SDL_CDROM"); /* ':' separated list of devices */ if ( SDLcdrom != NULL ) { char *cdpath, *delim; size_t len = SDL_strlen(SDLcdrom)+1; cdpath = SDL_stack_alloc(char, len); if ( cdpath != NULL ) { SDL_strlcpy(cdpath, SDLcdrom, len); SDLcdrom = cdpath; do { delim = SDL_strchr(SDLcdrom, ':'); if ( delim ) { *delim++ = '\0'; } if ( CheckDrive(SDLcdrom, &stbuf) > 0 ) { AddDrive(SDLcdrom, &stbuf); } if ( delim ) { SDLcdrom = delim; } else { SDLcdrom = NULL; } } while ( SDLcdrom ); SDL_stack_free(cdpath); } /* If we found our drives, there's nothing left to do */ if ( SDL_numcds > 0 ) { return(0); } } /* Scan the system for CD-ROM drives */ for ( i=0; checklist[i]; ++i ) { if ( checklist[i][0] == '?' ) { char *insert; exists = 1; for ( j=checklist[i][1]; exists; ++j ) { SDL_snprintf(drive, SDL_arraysize(drive), "/dev/%s", &checklist[i][3]); insert = SDL_strchr(drive, '?'); if ( insert != NULL ) { *insert = j; } switch (CheckDrive(drive, &stbuf)) { /* Drive exists and is a CD-ROM */ case 1: AddDrive(drive, &stbuf); break; /* Drive exists, but isn't a CD-ROM */ case 0: break; /* Drive doesn't exist */ case -1: exists = 0; break; } } } else { SDL_snprintf(drive, SDL_arraysize(drive), "/dev/%s", checklist[i]); if ( CheckDrive(drive, &stbuf) > 0 ) { AddDrive(drive, &stbuf); } } } return(0); } /* General ioctl() CD-ROM command function */ static int SDL_SYS_CDioctl(int id, int command, void *arg) { int retval; retval = ioctl(id, command, arg); if ( retval < 0 ) { SDL_SetError("ioctl() error: %s", strerror(errno)); } return(retval); } static const char *SDL_SYS_CDName(int drive) { return(SDL_cdlist[drive]); } static int SDL_SYS_CDOpen(int drive) { return(open(SDL_cdlist[drive], (O_RDONLY|O_EXCL|O_NONBLOCK), 0)); } static int SDL_SYS_CDGetTOC(SDL_CD *cdrom) { struct ioc_toc_header toc; int i, okay; struct ioc_read_toc_entry entry; struct cd_toc_entry data; okay = 0; if ( SDL_SYS_CDioctl(cdrom->id, CDIOREADTOCHEADER, &toc) == 0 ) { cdrom->numtracks = toc.ending_track-toc.starting_track+1; if ( cdrom->numtracks > SDL_MAX_TRACKS ) { cdrom->numtracks = SDL_MAX_TRACKS; } /* Read all the track TOC entries */ for ( i=0; i<=cdrom->numtracks; ++i ) { if ( i == cdrom->numtracks ) { cdrom->track[i].id = 0xAA; /* CDROM_LEADOUT */ } else { cdrom->track[i].id = toc.starting_track+i; } entry.starting_track = cdrom->track[i].id; entry.address_format = CD_MSF_FORMAT; entry.data_len = sizeof(data); entry.data = &data; if ( SDL_SYS_CDioctl(cdrom->id, CDIOREADTOCENTRYS, &entry) < 0 ) { break; } else { cdrom->track[i].type = data.control; cdrom->track[i].offset = MSF_TO_FRAMES( data.addr.msf.minute, data.addr.msf.second, data.addr.msf.frame); cdrom->track[i].length = 0; if ( i > 0 ) { cdrom->track[i-1].length = cdrom->track[i].offset- cdrom->track[i-1].offset; } } } if ( i == (cdrom->numtracks+1) ) { okay = 1; } } return(okay ? 0 : -1); } /* Get CD-ROM status */ static CDstatus SDL_SYS_CDStatus(SDL_CD *cdrom, int *position) { CDstatus status; struct ioc_toc_header toc; struct ioc_read_subchannel info; struct cd_sub_channel_info data; info.address_format = CD_MSF_FORMAT; info.data_format = CD_CURRENT_POSITION; info.track = 0; info.data_len = sizeof(data); info.data = &data; if ( ioctl(cdrom->id, CDIOCREADSUBCHANNEL, &info) < 0 ) { if ( ERRNO_TRAYEMPTY(errno) ) { status = CD_TRAYEMPTY; } else { status = CD_ERROR; } } else { switch (data.header.audio_status) { case CD_AS_AUDIO_INVALID: case CD_AS_NO_STATUS: /* Try to determine if there's a CD available */ if (ioctl(cdrom->id,CDIOREADTOCHEADER,&toc)==0) status = CD_STOPPED; else status = CD_TRAYEMPTY; break; case CD_AS_PLAY_COMPLETED: status = CD_STOPPED; break; case CD_AS_PLAY_IN_PROGRESS: status = CD_PLAYING; break; case CD_AS_PLAY_PAUSED: status = CD_PAUSED; break; default: status = CD_ERROR; break; } } if ( position ) { if ( status == CD_PLAYING || (status == CD_PAUSED) ) { *position = MSF_TO_FRAMES( data.what.position.absaddr.msf.minute, data.what.position.absaddr.msf.second, data.what.position.absaddr.msf.frame); } else { *position = 0; } } return(status); } /* Start play */ static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length) { struct ioc_play_msf playtime; FRAMES_TO_MSF(start, &playtime.start_m, &playtime.start_s, &playtime.start_f); FRAMES_TO_MSF(start+length, &playtime.end_m, &playtime.end_s, &playtime.end_f); #ifdef DEBUG_CDROM fprintf(stderr, "Trying to play from %d:%d:%d to %d:%d:%d\n", playtime.start_m, playtime.start_s, playtime.start_f, playtime.end_m, playtime.end_s, playtime.end_f); #endif ioctl(cdrom->id, CDIOCSTART, 0); return(SDL_SYS_CDioctl(cdrom->id, CDIOCPLAYMSF, &playtime)); } /* Pause play */ static int SDL_SYS_CDPause(SDL_CD *cdrom) { return(SDL_SYS_CDioctl(cdrom->id, CDIOCPAUSE, 0)); } /* Resume play */ static int SDL_SYS_CDResume(SDL_CD *cdrom) { return(SDL_SYS_CDioctl(cdrom->id, CDIOCRESUME, 0)); } /* Stop play */ static int SDL_SYS_CDStop(SDL_CD *cdrom) { return(SDL_SYS_CDioctl(cdrom->id, CDIOCSTOP, 0)); } /* Eject the CD-ROM */ static int SDL_SYS_CDEject(SDL_CD *cdrom) { return(SDL_SYS_CDioctl(cdrom->id, CDIOCEJECT, 0)); } /* Close the CD-ROM handle */ static void SDL_SYS_CDClose(SDL_CD *cdrom) { close(cdrom->id); } void SDL_SYS_CDQuit(void) { int i; if ( SDL_numcds > 0 ) { for ( i=0; i<SDL_numcds; ++i ) { SDL_free(SDL_cdlist[i]); } SDL_numcds = 0; } } #endif /* SDL_CDROM_OPENBSD */