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Several usb requests are needed to allow a USB3 link to enter U1/U2 hardware link power management LPM states. Reorder these requests and send the more significant and likely to succeed first. This is similar to the change done for disabling LPM Enable LPM by first sending requests to the upstream hub of the device SetPortFeature(U1_TIMEOUT) SetPortFeature(U2_TIMEOUT) These are more likely to succeed due to the shorter path, and LPM can be considered enabled as link may go to U1/U2 LPM states after those. Send the requests to the device after this, they allow the device to initialte U1/U2 link transitions. Hub can already initiate U1/U2 SetFeature(U1_ENABLE) SetFeature(U2_ENABLE) Fail fast and bail out if a requests to the device fails. This changes device initated LPM policy a bit. Device is no longer able to initiate U2 if it failed or is not allowed to initiate U1. Enabling and disabling Link power management is done as part of hub work. Avoid trying to send additional USB requests to a device when there are known issues. It just causes hub work to block for even longer. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20250314142000.93090-5-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 reStructuredText 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.