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d360870a5b
Drivers of ALSA firewire stack can process packets for IT/IR context in process context when the process operates ALSA PCM character device by calling ioctl(2) with some requests. The ioctl requests are: * SNDRV_PCM_IOCTL_HWSYNC * SNDRV_PCM_IOCTL_SYNC_PTR * SNDRV_PCM_IOCTL_REWIND * SNDRV_PCM_IOCTL_FORWARD * SNDRV_PCM_IOCTL_WRITEI_FRAMES * SNDRV_PCM_IOCTL_READI_FRAMES * SNDRV_PCM_IOCTL_WRITEN_FRAMES * SNDRV_PCM_IOCTL_READN_FRAMES This means that general application can process PCM frames apart from hardware IRQ invocation, even if they are programmed by either IRQ-based scheduling model or Timer-based scheduling model. This commit add support for Timer-based scheduling model by allowing PCM runtime to suppress both process wakeup per period and scheduling hardware IRQ. SNDRV_PCM_INFO_BATCH is obsoleted since ALSA IEC 61883-1/6 packet streaming engine can report the number of transferred PCM frames within PCM period boundary. The granularity equals to SYT_INTERVAL in blocking transmission. In non-blocking transmission, it doesn't equal to SYT_INTERVAL but doesn't exceed. This patch is tested with PulseAudio, and --sched-model option of axfer with fix against the issue reported at: * https://lore.kernel.org/alsa-devel/687f9871-7484-1370-04d1-9c968e86f72b@linux.intel.com/#r Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Link: https://lore.kernel.org/r/20210527123253.174315-1-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai <tiwai@suse.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.