Stop endpoint command fails with "context state error" if the endpoint is already stopped. This case was observed when a previous URB cancel had just completed and rang the doorbell to restart the ring, when a new URB cancel queued a stop endpoint command. >From xHC hardware pov the endpoint had not yet started, so the stop endpoint command failed with context state error. Right after this the doorbell ring took effect and ring was restarted. Interrupt handler saw a stop endpoint command completion event with "context state error" and discovered that the ring was back up in running state. flushing the write reduces these cases in stress testing, but does not completely remove the issue. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20210129130044.206855-15-mathias.nyman@linux.intel.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.
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