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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
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<HTML
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>SDL_UserEvent</TITLE
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><H1
><A
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>SDL_UserEvent</A
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><DIV
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><A
NAME="AEN4181"
></A
><H2
>Name</H2
>SDL_UserEvent&nbsp;--&nbsp;A user-defined event type</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4184"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct{
  Uint8 type;
  int code;
  void *data1;
  void *data2;
} SDL_UserEvent;</PRE
></DIV
><DIV
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><A
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><H2
>Structure Data</H2
><DIV
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><A
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></A
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><TABLE
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><TT
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></TT
></TD
><TD
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><TT
CLASS="LITERAL"
>SDL_USEREVENT</TT
> through to <TT
CLASS="LITERAL"
>SDL_NUMEVENTS-1</TT
></TD
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>code</I
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>User defined event code</TD
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><TR
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><TT
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>data1</I
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>User defined data pointer</TD
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><H2
>Description</H2
><P
><SPAN
CLASS="STRUCTNAME"
>SDL_UserEvent</SPAN
> is in the <TT
CLASS="STRUCTFIELD"
><I
>user</I
></TT
> member of the structure <A
HREF="sdlevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
></A
>. This event is unique, it is never created by SDL but only by the user. The event can be pushed onto the event queue using <A
HREF="sdlpushevent.html"
><TT
CLASS="FUNCTION"
>SDL_PushEvent</TT
></A
>. The contents of the structure members or completely up to the programmer, the only requirement is that <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
> is a value from <TT
CLASS="LITERAL"
>SDL_USEREVENT</TT
> to <TT
CLASS="LITERAL"
>SDL_NUMEVENTS-1</TT
> (inclusive).</P
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><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>SDL_Event event;

event.type = SDL_USEREVENT;
event.user.code = my_event_code;
event.user.data1 = significant_data;
event.user.data2 = 0;
SDL_PushEvent(&#38;event);</PRE
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>,
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