view docs/html/general.html @ 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 e5bc29de3f0a
children 355632dca928
line wrap: on
line source

<HTML
><HEAD
><TITLE
>General</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.64
"><LINK
REL="HOME"
TITLE="SDL Library Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="SDL Reference"
HREF="reference.html"><LINK
REL="PREVIOUS"
TITLE="SDL Reference"
HREF="reference.html"><LINK
REL="NEXT"
TITLE="SDL_Init"
HREF="sdlinit.html"><META
NAME="KEYWORD"
CONTENT="general"><META
NAME="KEYWORD"
CONTENT="function"></HEAD
><BODY
CLASS="CHAPTER"
BGCOLOR="#FFF8DC"
TEXT="#000000"
LINK="#0000ee"
VLINK="#551a8b"
ALINK="#ff0000"
><DIV
CLASS="NAVHEADER"
><TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>SDL Library Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="reference.html"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlinit.html"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="GENERAL"
>Chapter 5. General</A
></H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="sdlinit.html"
>SDL_Init</A
> &#8212; Initializes SDL</DT
><DT
><A
HREF="sdlinitsubsystem.html"
>SDL_InitSubSystem</A
> &#8212; Initialize subsystems</DT
><DT
><A
HREF="sdlquitsubsystem.html"
>SDL_QuitSubSystem</A
> &#8212; Shut down a subsystem</DT
><DT
><A
HREF="sdlquit.html"
>SDL_Quit</A
> &#8212; Shut down SDL</DT
><DT
><A
HREF="sdlwasinit.html"
>SDL_WasInit</A
> &#8212; Check which subsystems are initialized</DT
><DT
><A
HREF="sdlgeterror.html"
>SDL_GetError</A
> &#8212; Get SDL error string</DT
></DL
></DIV
><P
>Before SDL can be used in a program it must be initialized with <A
HREF="sdlinit.html"
><TT
CLASS="FUNCTION"
>SDL_Init</TT
></A
>. <TT
CLASS="FUNCTION"
>SDL_Init</TT
> initializes all the subsystems that the user requests (video, audio, joystick, timers and/or cdrom). Once SDL is initialized with <TT
CLASS="FUNCTION"
>SDL_Init</TT
> subsystems can be shut down and initialized as needed using <A
HREF="sdlinitsubsystem.html"
><TT
CLASS="FUNCTION"
>SDL_InitSubSystem</TT
></A
> and <A
HREF="sdlquitsubsystem.html"
><TT
CLASS="FUNCTION"
>SDL_QuitSubSystem</TT
></A
>.</P
><P
>SDL must also be shut down before the program exits to make sure it cleans up correctly. Calling <A
HREF="sdlquit.html"
><TT
CLASS="FUNCTION"
>SDL_Quit</TT
></A
> shuts down all subsystems and frees any resources allocated to SDL.</P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="reference.html"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="sdlinit.html"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL Reference</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="reference.html"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>SDL_Init</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>