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+'\" te
+.\"  Copyright (c) 2005, 4Front Technologies 2005\&.
+.TH ossddk_dmap_get_fragsize 9ossddk "12 Sep 2005" "SunOS 5.10" "OSS DDK Services"
+.SH "NAME"
+ossddk_dmap_get_fragsize, ossddk_dmap_set_fragsize, ossddk_dmap_get_numfrags, ossddk_dmap_set_numfrags \- Set/get DMA buffer partitioning parameters
+.PP
+.SH "SYNOPSIS"
+.nf
+#include <sys/soundcard.h>
+.LP
+#include <sys/ossddk/ossddk.h>
+.fi
+.LP
+\fBint\fR ossddk_dmap_get_fragsize(\fBdmap_t *\fIdmap\fP);
+\fBint\fR ossddk_dmap_get_numfrags(\fBdmap_t *\fIdmap\fP);
+\fBvoid\fR ossddk_dmap_set_fragsize(\fBdmap_t *\fIdmap\fP, \fBint \fIsize\fP);
+\fBvoid\fR ossddk_dmap_set_numfrags(\fBdmap_t *\fIdmap\fP, \fBint \fInfrags\fP);
+.PP
+.SH "INTERFACE LEVEL"
+.PP
+Open Sound System specific (OSS 4.0 DDK)\&.
+.PP
+.SH "ARGUMENTS"
+.PP
+.sp
+.ne 2
+.mk
+\fB\fIdmap\fR
+.in +16n
+.rt
+Audio buffer handle.
+.in -16n
+.sp
+.ne 2
+.mk
+\fB\fInfrags\fR
+.in +16n
+.rt
+Number of fragments.
+.in -16n
+.sp
+.ne 2
+.mk
+\fB\fIsize\fR
+.in +16n
+.rt
+Fragment size in bytes.
+.in -16n
+.PP
+.SH "DESCRIPTION"
+.PP
+The DMA buffer maintained by OSS audio core is divided to number of fragments
+with equal size. The driver should program the device to raice an interrupt
+on every fragment boundary. The driver can get the fragment size (in bytes) by
+calling \fIossddk_dmap_get_fragsize\fR. If the number of fragments is needed it
+can be obtained with \fIossddk_dmap_get_numfrags\fR.
+.PP
+It is also possible to set these parameters but it should be avoided if
+possible. Changing these parameters may cause unpredictable problems and is
+bot supported by 4Front Technologies. If the driver changes these parameters it must ensure that fragment_size*num_fragments doesn't (even temporarily) become
+larger than the total size of the allocated buffer. Otherwise the result will be
+something else than what was intended by the driver. These parameters can only
+be changed in the prepare_for_input and prepare_for_output methods of the
+driver. As a side effect the value returned by \fIossddk_dmap_get_buffused(9ossddk)\fR will also get changed automatically. An undesired side effect is that
+the fragment size possibly reported to the application will no longer be valid
+which probably breaks some incorrectly designed applications.
+.PP
+.SH "RETURN VALUES"
+\fIossddk_dmap_get_fragsize\fR returns the current fragment size in bytes.
+.LP
+\fIossddk_dmap_get_numfrags\fR returns the number of fragments currently in use.
+.PP
+.SH "SEE ALSO"
+.PP
+\fIWriting Sound Device Drivers with OSS DDK\fR
+.LP
+\fIOpen Sound System Programmer's Guide\fR