It is plausible that the hardware interrupts a host only when GIS goes from zero to one. GIS is formed by OR-ing multiple hardware statuses, so it's possible that a previously cleared status gets set again while another status has not been cleared yet. Thus, there will be no new interrupt as GIS always stayed set. If we don't re-examine GIS then we can leave it set and never get another interrupt again. Without this change I frequently saw a problem where snd_hda would stop working. Setting dev.hdac.1.polling=1 would bring it back to life and afterwards I could set polling back to zero. Sometimes the problem started right after a boot, sometimes it happened after resuming from S3, frequently it would occur when sound output and input are active concurrently (such as during conferencing). I looked at HDAC_INTSTS while the sound was not working and I saw that both HDAC_INTSTS_GIS and HDAC_INTSTS_CIS were set, but there were no interrupts. I have collected some statistics over a period of several days about how many loops (calls to hdac_one_intr) the new code did for a single interrupt: +--------+--------------+ |Loops |Times Happened| +--------+--------------+ |0 |301 | |1 |12857746 | |2 |280 | |3 |2 | |4+ |0 | +--------+--------------+ I believe that previously the sound would get stuck each time we had to loop more than once. The tested hardware is: hdac1: <AMD (0x15e3) HDA Controller> mem 0xfe680000-0xfe687fff at device 0.6 on pci4 hdacc1: <Realtek ALC269 HDA CODEC> at cad 0 on hdac1 No objections: mav MFC after: 5 weeks Differential Revision: https://reviews.freebsd.org/D25128 |
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bin | ||
cddl | ||
contrib | ||
crypto | ||
etc | ||
gnu | ||
include | ||
kerberos5 | ||
lib | ||
libexec | ||
release | ||
rescue | ||
sbin | ||
secure | ||
share | ||
stand | ||
sys | ||
targets | ||
tests | ||
tools | ||
usr.bin | ||
usr.sbin | ||
.arcconfig | ||
.arclint | ||
.cirrus.yml | ||
.clang-format | ||
.gitattributes | ||
.gitignore | ||
COPYRIGHT | ||
LOCKS | ||
MAINTAINERS | ||
Makefile | ||
Makefile.inc1 | ||
Makefile.libcompat | ||
Makefile.sys.inc | ||
ObsoleteFiles.inc | ||
README | ||
README.md | ||
RELNOTES | ||
UPDATING |
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
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The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
Source Roadmap:
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and Distribution License.
contrib Packages contributed by 3rd parties.
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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.
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release Release building Makefile & associated tools.
rescue Build system for statically linked /rescue utilities.
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secure Cryptographic libraries and commands.
share Shared resources.
stand Boot loader sources.
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used in release builds. NOTES contains documentation of
all possible entries.
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