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commit f7b77ebe6d2f49c7747b2d619586d1aa33f9ea91 upstream. This fixes a problem where closing the tuner would leave it in a state where it would not tune to any channel when reopened. This problem was discovered as part of https://github.com/hselasky/webcamd/issues/16. Since adap->id is 0 or 1, this bit-shift overflows, which is undefined behavior. The driver still worked in practice as the overflow would in most environments result in 0, which rendered the line a no-op. When running the driver as part of webcamd however, the overflow could lead to 0xff due to optimizations by the compiler, which would, in the end, improperly shut down the tuner. The bug is a regression introduced in the commit referenced below. The present patch causes identical behavior to before that commit for adap->id equal to 0 or 1. The driver does not contain support for dib0700 devices with more adapters, assuming such even exist. Tests have been performed with the Xbox One Digital TV Tuner on amd64. Not all dib0700 devices are expected to be affected by the regression; this code path is only taken by those with incorrect endpoint numbers. Link: https://lore.kernel.org/linux-media/1d2fc36d94ced6f67c7cc21dcc469d5e5bdd8201.1632689033.git.mchehab+huawei@kernel.org Cc: stable@vger.kernel.org Fixes: 7757ddda6f4f ("[media] DiB0700: add function to change I2C-speed") Signed-off-by: Michael Kuron <michael.kuron@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.