Mercurial > sdl-ios-xcode
annotate src/thread/linux/SDL_syscond.c @ 765:4c2ba6161939
Editors Note: The original patch was modified to use SDL_Delay() instead of
nanosleep because nanosleep may not be portable to all systems
using SDL with the ALSA backend. This may be a moot point with
the switch to blocking writes anyway...
Date: Sat, 27 Dec 2003 21:47:36 +0100
From: Michel Daenzer
To: Debian Bug Tracking System
Subject: [SDL] Bug#225252: [PATCH] ALSA fixes
Package: libsdl1.2debian-all
Version: 1.2.6-2
Severity: normal
Tags: patch
For SDL 1.2.6, the ALSA backend was changed to call snd_pcm_open() with
SND_PCM_NONBLOCK. That's a good idea per se, however, it causes high CPU
usage, interrupted sound and stuttering in some games here. Taking a nanosleep
whenever snd_pcm_writei() returns -EAGAIN fixes this, but I think it's more
efficient to use blocking mode for the actual sound playback. Feedback from the
SDL and ALSA lists appreciated.
The patch also fixes the default ALSA device to be used.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 04 Jan 2004 15:40:50 +0000 |
| parents | f6ffac90895c |
| children | b8d311d90021 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
|
297
f6ffac90895c
Updated copyright information for 2002
Sam Lantinga <slouken@libsdl.org>
parents:
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changeset
|
3 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga |
| 0 | 4 |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 of the License, or (at your option) any later version. | |
| 9 | |
| 10 This library is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
|
252
e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
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|
20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 #ifdef SAVE_RCSID | |
| 24 static char rcsid = | |
| 25 "@(#) $Id$"; | |
| 26 #endif | |
| 27 | |
| 28 #ifdef linux | |
| 29 /* Look to see if glibc is available, and if so, what version */ | |
| 30 #include <features.h> | |
| 31 | |
| 32 #if (__GLIBC__ == 2) && (__GLIBC_MINOR__ == 0) | |
| 33 #warning Working around a bug in glibc 2.0 pthreads | |
| 34 #undef SDL_USE_PTHREADS | |
| 35 /* The bug is actually a problem where threads are suspended, but don't | |
| 36 wake up when the thread manager sends them a signal. This is a problem | |
| 37 with thread creation too, but it happens less often. :-/ | |
| 38 We avoid this by using System V IPC for mutexes. | |
| 39 */ | |
| 40 #endif /* glibc 2.0 */ | |
| 41 #endif /* linux */ | |
| 42 | |
| 43 #ifdef SDL_USE_PTHREADS | |
| 44 | |
| 45 #include <sys/time.h> | |
| 46 #include <unistd.h> | |
| 47 #include <errno.h> | |
| 48 #include <stdlib.h> | |
| 49 #include <pthread.h> | |
| 50 | |
| 51 #include "SDL_error.h" | |
| 52 #include "SDL_thread.h" | |
| 53 #include "SDL_sysmutex_c.h" | |
| 54 | |
| 55 | |
| 56 #if defined(PTHREAD_NO_RECURSIVE_MUTEX) && !defined(__bsdi__) | |
| 57 #error You need to use the generic condition variable implementation | |
| 58 #endif | |
| 59 | |
| 60 struct SDL_cond | |
| 61 { | |
| 62 pthread_cond_t cond; | |
| 63 }; | |
| 64 | |
| 65 /* Create a condition variable */ | |
| 66 SDL_cond * SDL_CreateCond(void) | |
| 67 { | |
| 68 SDL_cond *cond; | |
| 69 | |
| 70 cond = (SDL_cond *) malloc(sizeof(SDL_cond)); | |
| 71 if ( cond ) { | |
| 72 if ( pthread_cond_init(&cond->cond, NULL) < 0 ) { | |
| 73 SDL_SetError("pthread_cond_init() failed"); | |
| 74 free(cond); | |
| 75 cond = NULL; | |
| 76 } | |
| 77 } | |
| 78 return(cond); | |
| 79 } | |
| 80 | |
| 81 /* Destroy a condition variable */ | |
| 82 void SDL_DestroyCond(SDL_cond *cond) | |
| 83 { | |
| 84 if ( cond ) { | |
| 85 pthread_cond_destroy(&cond->cond); | |
| 86 free(cond); | |
| 87 } | |
| 88 } | |
| 89 | |
| 90 /* Restart one of the threads that are waiting on the condition variable */ | |
| 91 int SDL_CondSignal(SDL_cond *cond) | |
| 92 { | |
| 93 int retval; | |
| 94 | |
| 95 if ( ! cond ) { | |
| 96 SDL_SetError("Passed a NULL condition variable"); | |
| 97 return -1; | |
| 98 } | |
| 99 | |
| 100 retval = 0; | |
| 101 if ( pthread_cond_signal(&cond->cond) != 0 ) { | |
| 102 SDL_SetError("pthread_cond_signal() failed"); | |
| 103 retval = -1; | |
| 104 } | |
| 105 return retval; | |
| 106 } | |
| 107 | |
| 108 /* Restart all threads that are waiting on the condition variable */ | |
| 109 int SDL_CondBroadcast(SDL_cond *cond) | |
| 110 { | |
| 111 int retval; | |
| 112 | |
| 113 if ( ! cond ) { | |
| 114 SDL_SetError("Passed a NULL condition variable"); | |
| 115 return -1; | |
| 116 } | |
| 117 | |
| 118 retval = 0; | |
| 119 if ( pthread_cond_broadcast(&cond->cond) != 0 ) { | |
| 120 SDL_SetError("pthread_cond_broadcast() failed"); | |
| 121 retval = -1; | |
| 122 } | |
| 123 return retval; | |
| 124 } | |
| 125 | |
| 126 int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms) | |
| 127 { | |
| 128 int retval; | |
| 129 struct timeval delta; | |
| 130 struct timespec abstime; | |
| 131 | |
| 132 if ( ! cond ) { | |
| 133 SDL_SetError("Passed a NULL condition variable"); | |
| 134 return -1; | |
| 135 } | |
| 136 | |
| 137 gettimeofday(&delta, NULL); | |
| 138 | |
| 139 abstime.tv_sec = delta.tv_sec + (ms/1000); | |
|
244
dc660aee7d7d
Fixed timeout in Linux condition variable implementation
Sam Lantinga <slouken@libsdl.org>
parents:
0
diff
changeset
|
140 abstime.tv_nsec = (delta.tv_usec + (ms%1000) * 1000) * 1000; |
|
dc660aee7d7d
Fixed timeout in Linux condition variable implementation
Sam Lantinga <slouken@libsdl.org>
parents:
0
diff
changeset
|
141 if ( abstime.tv_nsec > 1000000000 ) { |
| 0 | 142 abstime.tv_sec += 1; |
|
244
dc660aee7d7d
Fixed timeout in Linux condition variable implementation
Sam Lantinga <slouken@libsdl.org>
parents:
0
diff
changeset
|
143 abstime.tv_nsec -= 1000000000; |
| 0 | 144 } |
| 145 | |
| 146 tryagain: | |
| 147 retval = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime); | |
| 148 switch (retval) { | |
| 149 case EINTR: | |
| 150 goto tryagain; | |
| 151 break; | |
| 152 case ETIMEDOUT: | |
| 153 retval = SDL_MUTEX_TIMEDOUT; | |
| 154 break; | |
| 155 case 0: | |
| 156 break; | |
| 157 default: | |
| 158 SDL_SetError("pthread_cond_timedwait() failed"); | |
| 159 retval = -1; | |
| 160 break; | |
| 161 } | |
| 162 return retval; | |
| 163 } | |
| 164 | |
| 165 /* Wait on the condition variable, unlocking the provided mutex. | |
| 166 The mutex must be locked before entering this function! | |
| 167 */ | |
| 168 int SDL_CondWait(SDL_cond *cond, SDL_mutex *mutex) | |
| 169 { | |
| 170 int retval; | |
| 171 | |
| 172 if ( ! cond ) { | |
| 173 SDL_SetError("Passed a NULL condition variable"); | |
| 174 return -1; | |
| 175 } | |
| 176 | |
| 177 retval = 0; | |
| 178 if ( pthread_cond_wait(&cond->cond, &mutex->id) != 0 ) { | |
| 179 SDL_SetError("pthread_cond_wait() failed"); | |
| 180 retval = -1; | |
| 181 } | |
| 182 return retval; | |
| 183 } | |
| 184 | |
| 185 #else /* Use semaphore implementation */ | |
| 186 | |
| 187 #include "generic/SDL_syscond.c" | |
| 188 | |
| 189 #endif /* SDL_USE_PTHREADS */ |