* 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.

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/*
	MiNT audio driver

	Patrice Mandin
*/

#ifndef _SDL_mintaudio_h
#define _SDL_mintaudio_h

#include "../SDL_sysaudio.h"
#include "SDL_mintaudio_stfa.h"

/* Hidden "this" pointer for the audio functions */
#define _THIS	SDL_AudioDevice *this

/* 16 predivisors with 3 clocks max. */
#define MINTAUDIO_maxfreqs		(16*3)		

typedef struct {
	Uint32	frequency;
	Uint32	masterclock;
	Uint32	predivisor;
	int	gpio_bits;	/* in case of external clock */
} mint_frequency_t;

struct SDL_PrivateAudioData {
	mint_frequency_t	frequencies[MINTAUDIO_maxfreqs];
	int 	freq_count;		/* Number of frequencies in the array */
	int		numfreq;		/* Number of selected frequency */
};

/* Old variable names */

#define MINTAUDIO_frequencies	(this->hidden->frequencies)
#define MINTAUDIO_freqcount		(this->hidden->freq_count)
#define MINTAUDIO_numfreq		(this->hidden->numfreq)

/* _MCH cookie (values>>16) */
enum {
	MCH_ST=0,
	MCH_STE,
	MCH_TT,
	MCH_F30,
	MCH_CLONE,
	MCH_ARANYM
};

/* Master clocks for replay frequencies */
#define MASTERCLOCK_STE		8010666		/* Not sure of this one */
#define MASTERCLOCK_TT		16107953	/* Not sure of this one */
#define MASTERCLOCK_FALCON1	25175000
#define MASTERCLOCK_FALCON2	32000000	/* Only usable for DSP56K */
#define MASTERCLOCK_FALCONEXT	-1		/* Clock on DSP56K port, unknown */
#define MASTERCLOCK_44K		22579200	/* Standard clock for 44.1 Khz */
#define MASTERCLOCK_48K		24576000	/* Standard clock for 48 Khz */

/* Master clock predivisors */
#define MASTERPREDIV_STE	160
#define MASTERPREDIV_TT		320
#define MASTERPREDIV_FALCON	256
#define MASTERPREDIV_MILAN	256

/* MFP 68901 interrupt sources */
enum {
	MFP_PARALLEL=0,
	MFP_DCD,
	MFP_CTS,
	MFP_BITBLT,
	MFP_TIMERD,
	MFP_BAUDRATE=MFP_TIMERD,
	MFP_TIMERC,
	MFP_200HZ=MFP_TIMERC,
	MFP_ACIA,
	MFP_DISK,
	MFP_TIMERB,
	MFP_HBLANK=MFP_TIMERB,
	MFP_TERR,
	MFP_TBE,
	MFP_RERR,
	MFP_RBF,
	MFP_TIMERA,
	MFP_DMASOUND=MFP_TIMERA,
	MFP_RING,
	MFP_MONODETECT
};

/* Xbtimer() timers */
enum {
	XB_TIMERA=0,
	XB_TIMERB,
	XB_TIMERC,
	XB_TIMERD
};

/* Variables */
extern SDL_AudioDevice *SDL_MintAudio_device;
extern Uint8 *SDL_MintAudio_audiobuf[2];	/* Pointers to buffers */
extern unsigned long SDL_MintAudio_audiosize;		/* Length of audio buffer=spec->size */
extern volatile unsigned short SDL_MintAudio_numbuf;		/* Buffer to play */
extern volatile unsigned short SDL_MintAudio_mutex;
extern cookie_stfa_t *SDL_MintAudio_stfa;
extern volatile unsigned long SDL_MintAudio_clocktics;
extern unsigned short SDL_MintAudio_hasfpu;	/* To preserve fpu registers if needed */

/* MiNT thread variables */
extern SDL_bool	SDL_MintAudio_mint_present;
extern SDL_bool SDL_MintAudio_quit_thread;
extern SDL_bool SDL_MintAudio_thread_finished;
extern long SDL_MintAudio_thread_pid;

/* Functions */
void SDL_MintAudio_Callback(void);
void SDL_MintAudio_AddFrequency(_THIS, Uint32 frequency, Uint32 clock,
	Uint32 prediv, int gpio_bits);
int SDL_MintAudio_SearchFrequency(_THIS, int desired_freq);
void SDL_MintAudio_CheckFpu(void);

/* MiNT thread functions */
int SDL_MintAudio_Thread(long param);
void SDL_MintAudio_WaitThread(void);

/* ASM interrupt functions */
void SDL_MintAudio_GsxbInterrupt(void);
void SDL_MintAudio_EmptyGsxbInterrupt(void);
void SDL_MintAudio_XbiosInterruptMeasureClock(void);
void SDL_MintAudio_XbiosInterrupt(void);
void SDL_MintAudio_Dma8Interrupt(void);
void SDL_MintAudio_StfaInterrupt(void);

#endif /* _SDL_mintaudio_h */