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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Takashi IwaiandGreg Kroah-Hartman
8c28274b2d
[ Upstream commit4f9d674377] The low-latency mode of USB-audio driver uses a similar approach like the implicit feedback mode but it has an explicit queuing at the trigger start time. The difference is, however, that no packet will be handled any longer after all queued packets are handled but no enough data is fed. In the case of implicit feedback mode, the capture-side packet handling triggers the re-queuing, and this checks the XRUN. OTOH, in the low-latency mode, it just stops without XRUN notification unless any new action is taken from user-space via ack callback. For example, when you stop the stream in aplay, no XRUN is reported. This patch adds the XRUN check at the packet complete callback in the case all pending URBs are exhausted. Strictly speaking, this state doesn't match really with XRUN; in theory the application may queue immediately after this happens. But such behavior is only for 1-period configuration, which the USB-audio driver doesn't support. So we may conclude that this situation leads certainly to XRUN. A caveat is that the XRUN should be triggered only for the PCM RUNNING state, and not during DRAINING. This additional state check is put in notify_xrun(), too. Fixes:d5f871f89e("ALSA: usb-audio: Improved lowlatency playback support") Reported-by: Leonard Crestez <cdleonard@gmail.com> Link: https://lore.kernel.org/25d5b0d8-4efd-4630-9d33-7a9e3fa9dc2b@gmail.com Link: https://patch.msgid.link/20241128080446.1181-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.