143ba5c2d2
commit 181135bb20dcb184edd89817831b888eb8132741 upstream. Before adding this quirk, this (mechanical keyboard) device would not be recognized, logging: new full-speed USB device number 56 using xhci_hcd unable to read config index 0 descriptor/start: -32 chopping to 0 config(s) It would take dozens of plugging/unpuggling cycles for the keyboard to be recognized. Keyboard seems to simply work after applying this quirk. This issue had been reported by users in two places already ([1], [2]) but nobody tried upstreaming a patch yet. After testing I believe their suggested fix (DELAY_INIT + NO_LPM + DEVICE_QUALIFIER) was probably a little overkill. I assume this particular combination was tested because it had been previously suggested in [3], but only NO_LPM seems sufficient for this device. [1]: https://qiita.com/float168/items/fed43d540c8e2201b543 [2]: https://blog.kostic.dev/posts/making-the-realforce-87ub-work-with-usb30-on-Ubuntu/ [3]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1678477 Cc: stable@vger.kernel.org Signed-off-by: Nicolas Dumazet <ndumazet@google.com> Link: https://lore.kernel.org/r/20221109122946.706036-1-ndumazet@google.com 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.