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Alexander Motin fd578f6543 Make sound(4) more flexible in setting soft buffer and block sizes when
hardware imposes strict limitations on hard buffer and block sizes.

Previous code set soft buffer to be no smaller then hard buffer. On some
cards with fixed 64K physical buffer that caused up to 800ms play latency.
New code allows to set soft buffer size down to just two blocks of the hard
buffer and to not write more then that size ahead to the hardware buffer.
As result of that change I was able to reduce full practically measured
record-playback loop delay in those conditions down to only about 115ms
with theoretical playback latency of only about 50ms.

New code works fine for both vchans and direct cases. In both cases sound(4)
tries to follow hw.snd.latency_profile and hw.snd.latency values and
application-requested buffer and block sizes as much as limitation of two
hardware blocks allows.

Reviewed by:	silence on multimedia@
2012-01-31 21:46:28 +00:00
bin Add prototypes, ANSIfy functions definitions to reduce WARNS=6 output. 2012-01-25 08:42:19 +00:00
cddl Set SVN text/plain property for some shell scripts that 2012-01-28 00:17:17 +00:00
contrib Uupdate code to vendor rev. 4183 (release/2.8) 2012-01-29 22:20:28 +00:00
crypto Fix a problem whereby a corrupt DNS record can cause named to crash. [11:06] 2011-12-23 15:00:37 +00:00
etc Perform IPv6 DAD only in ifn_start. 2012-01-29 08:33:34 +00:00
games o Preserve argv[0] to use it later in usage(). 2012-01-28 15:29:43 +00:00
gnu Adopt to new layout of struct pcb. 2012-01-21 17:50:14 +00:00
include Only use the static assertion when __generic is available. 2012-01-17 20:22:10 +00:00
kerberos5 Don't support OpenLDAP during lib32 build. 2011-12-06 12:03:01 +00:00
lib Move descriptions of file caching commands out of the file locking section. 2012-01-28 18:35:10 +00:00
libexec Add support for GNU RELRO. 2012-01-30 19:52:17 +00:00
release Part of r230482 didn't actually work. Revert it for now. This means PR 2012-01-23 16:17:54 +00:00
rescue -lreadline is not required anymore. 2011-11-29 03:27:09 +00:00
sbin Add -e to set arbitrary kernel environment variables. 2012-01-31 15:32:05 +00:00
secure Force linker error when created shared library contains a relocation 2011-12-06 11:28:17 +00:00
share Add isci(4) driver for amd64 and i386 targets. 2012-01-31 19:38:18 +00:00
sys Make sound(4) more flexible in setting soft buffer and block sizes when 2012-01-31 21:46:28 +00:00
tools More mdconfig(8) tests. 2012-01-26 18:16:16 +00:00
usr.bin Always return 0 if the sysctl failed. 2012-01-29 20:39:42 +00:00
usr.sbin Fix a whitespace nit 2012-01-31 05:49:49 +00:00
COPYRIGHT Happy 2012 to FreeBSD users in Samoa. 2011-12-31 04:38:04 +00:00
LOCKS
MAINTAINERS Add isci(4) driver for amd64 and i386 targets. 2012-01-31 19:38:18 +00:00
Makefile Replace 'chflags' with 'file flags' in a comment, since 'chflags' 2011-11-20 20:05:47 +00:00
Makefile.inc1 Allow specification of build shell for the buildenv target. 2012-01-30 20:19:28 +00:00
Makefile.mips Retire TARGET_ABI. 2011-01-07 20:26:33 +00:00
ObsoleteFiles.inc Remove wtmpcvt(1). 2012-01-13 15:40:49 +00:00
README Add the cddl/ directory. 2010-11-14 11:32:56 +00:00
UPDATING For the mass rc.d changes, add a command line to make the update easier 2012-01-14 23:19:10 +00:00

This is the top level of the FreeBSD source directory.  This file
was last revised on:
$FreeBSD$

For copyright information, please see the file COPYRIGHT in this
directory (additional copyright information also exists for some
sources in this tree - please see the specific source directories for
more information).

The Makefile in this directory supports a number of targets for
building components (or all) of the FreeBSD source tree, the most
commonly used one being ``world'', which rebuilds and installs
everything in the FreeBSD system from the source tree except the
kernel, the kernel-modules and the contents of /etc.  The ``world''
target should only be used in cases where the source tree has not
changed from the currently running version.  See:
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html
for more information, including setting make(1) variables.

The ``buildkernel'' and ``installkernel'' targets build and install
the kernel and the modules (see below).  Please see the top of
the Makefile in this directory for more information on the
standard build targets and compile-time flags.

Building a kernel is a somewhat more involved process, documentation
for which can be found at:
   http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
And in the config(8) man page.
Note: If you want to build and install the kernel with the
``buildkernel'' and ``installkernel'' targets, you might need to build
world before.  More information is available in the handbook.

The sample kernel configuration files reside in the sys/<arch>/conf
sub-directory (assuming that you've installed the kernel sources), the
file named GENERIC being the one used to build your initial installation
kernel.  The file NOTES contains entries and documentation for all possible
devices, not just those commonly used.  It is the successor of the ancient
LINT file, but in contrast to LINT, it is not buildable as a kernel but a
pure reference and documentation file.


Source Roadmap:
---------------
bin		System/user commands.

cddl		Various commands and libraries under the Common Development
		and Distribution License.

contrib		Packages contributed by 3rd parties.

crypto		Cryptography stuff (see crypto/README).

etc		Template files for /etc.

games		Amusements.

gnu		Various commands and libraries under the GNU Public License.
		Please see gnu/COPYING* for more information.

include		System include files.

kerberos5	Kerberos5 (Heimdal) package.

lib		System libraries.

libexec		System daemons.

release		Release building Makefile & associated tools.

rescue		Build system for statically linked /rescue utilities.

sbin		System commands.

secure		Cryptographic libraries and commands.

share		Shared resources.

sys		Kernel sources.

tools		Utilities for regression testing and miscellaneous tasks.

usr.bin		User commands.

usr.sbin	System administration commands.


For information on synchronizing your source tree with one or more of
the FreeBSD Project's development branches, please see:

  http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html