On Wed, Dec 22, 2004 at 07:35:13PM +0100, Benjamin Herrenschmidt wrote: > On Wed, 2004-12-22 at 19:13 +0100, Benjamin Herrenschmidt wrote: > > This patch (which will be send upstream separately by the Alsa folks) fixes > > an signed vs. unsigned char problem in Alsa which was the cause of the Oops > > people were experiencing on ppc with OSS emulation and possibly other > > issues. > > Ok, actually, the one that will be commited upstream is a bit different, > here it is: > > > Summary: [ALSA] Fix the wrong sign of format data entries > > Fix suggested by Benjamin Herrenschmidt <[EMAIL PROTECTED]> > > On architectures like PPC, char is handled as "unsigned char", thus the > pcm_format_data table entries with -1 give a positive 255. This causes > Oops with OSS-emulation on such architectures. > > The patch simply adds the right signed/unsigned prefix to fix this problem. > > > Signed-off-by: Takashi Iwai <[EMAIL PROTECTED]> > > > --- linux/sound/core/pcm_misc.c 8 Jun 2004 16:57:28 -0000 1.12 > +++ linux/sound/core/pcm_misc.c 22 Dec 2004 18:07:29 -0000 1.14 > @@ -25,11 +25,14 @@ > #include <sound/pcm.h> > #define SND_PCM_FORMAT_UNKNOWN (-1) > > +/* NOTE: "signed" prefix must be given below since the default char is > + * unsigned on some architectures! > + */ > struct pcm_format_data { > - char width; /* bit width */ > - char phys; /* physical bit width */ > - char le; /* 0 = big-endian, 1 = little-endian, -1 = others */ > - char signd; /* 0 = unsigned, 1 = signed, -1 = others */ > + unsigned char width; /* bit width */ > + unsigned char phys; /* physical bit width */ > + signed char le; /* 0 = big-endian, 1 = little-endian, -1 = others */ > + signed char signd; /* 0 = unsigned, 1 = signed, -1 = others */ > unsigned char silence[8]; /* silence data to fill */ > };
Mmm, this does not apply to the 2.6.8 debian kernel-source package, which doesn't seem to have a pcm_format_data structure. Do we need a backport of it to 2.6.8, or was the problem not present then ? Friendly, Sven Luther