[ Upstream commit 66aad7d8d3ec5a3a8ec2023841bcec2ded5f65c9 ] In ACM support for sending breaks to devices is optional. If a device says that it doenot support sending breaks, the host must respect that. Given the number of optional features providing tty operations for each combination is not practical and errors need to be returned dynamically if unsupported features are requested. In case a device does not support break, we want the tty layer to treat that like it treats drivers that statically cannot support sending a break. It ignores the inability and does nothing. This patch uses EOPNOTSUPP to indicate that. Signed-off-by: Oliver Neukum <oneukum@suse.com> Fixes: 9e98966c7bb94 ("tty: rework break handling") Link: https://lore.kernel.org/r/20231207132639.18250-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 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.
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