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Genode OS Framework
armcpluspluscppframeworkgenodegoahypervisorlinuxmicrokernelnovaobject-capabilitiesoperating-systemosdevriscvsculpt-ossel4virtualizationx86
3d2b0cab93
In the same vein as the terminal and block I/O controls, the sound controls are implemented via poperty files and match the OSS API ([1] features a nice overview while [2] is v3 and [3] gives in-depth information on the current v4.x API we eventually might want to implement). [1] https://wiki.freebsd.org/RyanBeasley/ioctlref/ [2] http://www.opensound.com/pguide/oss.pdf [3] http://manuals.opensound.com/developer/ The controls currently implemented are the ones used by the cmus OSS output plugin, which was the driving factor behind the implementation. It uses the obsolete (v3) API and does not check if the requested parameter was actually set, which should be done according to the official OSS documentation. At the moment it is not possible to set or rather change any parameters. In case the requested setting differs from the parameters of the underlying Audio_out session - in contrast to the suggestion in the OSS manual - we do not silently adjust the parameters returned to the callee but outright fail the I/O control operation. The following list contains all currently handled I/O controls. * SNDCTL_DSP_CHANNELS sets the number of channels. We return the available channels here and return ENOTSUP if it differs from the requested number of channels. * SNDCTL_DSP_GETOSPACE returns amount of playback data that can be written without blocking. For now it amounts the space left in the Audio_out packet-stream. * SNDCTL_DSP_POST forces playback to start. We do nothing and return success. * SNDCTL_DSP_RESET is supposed to reset the device when it is active before any parameters are changed. We do nothing and return success. * SNDCTL_DSP_SAMPLESIZE sets the sample size. We return the sample size of the underlying Audio_out session and return ENOTSUP if it differs from the requested number of channels. * SNDCTL_DSP_SETFRAGMENT sets the buffer size hint. We ignore the hint and return success. * SNDCTL_DSP_SPEED sets the samplerate. For now, we always return the rate of the underlying Audio_out session and return ENOTSUP if it differs from the requested one. This commit serves as a starting point for further implementing the OSS API by exploring more users, e.g. as VirtualBox/Qt5/SDL2 audio backend or a more sophisticated progam like sndiod. Issue #3891. |
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=================================
Genode Operating System Framework
=================================
This is the source tree of the reference implementation of the Genode OS
architecture. For a general overview about the architecture, please refer to
the project's official website:
:Official project website for the Genode OS Framework:
[https://genode.org/documentation/general-overview]
The current implementation can be compiled for 8 different kernels: Linux,
L4ka::Pistachio, L4/Fiasco, OKL4, NOVA, Fiasco.OC, seL4, and a custom
kernel for running Genode directly on ARM-based hardware. Whereas the Linux
version serves us as development vehicle and enables us to rapidly develop the
generic parts of the system, the actual target platforms of the framework are
microkernels. There is no "perfect" microkernel - and neither should there be
one. If a microkernel pretended to be fit for all use cases, it wouldn't be
"micro". Hence, all microkernels differ in terms of their respective features,
complexity, and supported hardware architectures.
Genode allows the use of each of the kernels listed above with a rich set of
device drivers, protocol stacks, libraries, and applications in a uniform way.
For developers, the framework provides an easy way to target multiple different
kernels instead of tying the development to a particular kernel technology. For
kernel developers, Genode contributes advanced workloads, stress-testing their
kernel, and enabling a variety of application use cases that would not be
possible otherwise. For users and system integrators, it enables the choice of
the kernel that fits best with the requirements at hand for the particular
usage scenario.
Documentation
#############
The primary documentation is the book "Genode Foundations", which is available
on the front page of Genode website:
:Download the book "Genode Foundations":
[https://genode.org]
The book describes Genode in a holistic and comprehensive way. It equips you
with a thorough understanding of the architecture, assists developers with the
explanation of the development environment and system configuration, and
provides a look under the hood of the framework. Furthermore, it contains the
specification of the framework's programming interface.
The project has a quarterly release cycle. Each version is accompanied with
detailed release documentation, which is available at the documentation
section of the project website:
:Release documentation:
[https://genode.org/documentation/release-notes/]
Directory overview
##################
The source tree is composed of the following subdirectories:
:'doc':
This directory contains general documentation. Please consider the following
document for a quick guide to get started with the framework:
! doc/getting_started.txt
If you are curious about the ready-to-use components that come with the
framework, please review the components overview:
! doc/components.txt
:'repos':
This directory contains the so-called source-code repositories of Genode.
Please refer to the README file in the 'repos' directory to learn more
about the roles of the individual repositories.
:'tool':
Source-code management tools and scripts. Please refer to the README file
contained in the directory.
:'depot' and 'public':
Local depot and public archive of Genode packages. Please refer to
! doc/depot.txt
for more details.
Additional community-maintained components
##########################################
The components found within the main source tree are complemented by a growing
library of additional software, which can be seamlessly integrated into Genode
system scenarios.
:Genode-world repository:
[https://github.com/genodelabs/genode-world]
Contact
#######
The best way to get in touch with Genode developers and users is the project's
mailing list. Please feel welcome to join in!
:Genode Mailing Lists:
[https://genode.org/community/mailing-lists]
Commercial support
##################
The driving force behind the Genode OS Framework is the German company Genode
Labs. The company offers commercial licensing, trainings, support, and
contracted development work:
:Genode Labs website:
[https://www.genode-labs.com]