mainlining shenanigans
e146caf303
The host needs to tell the device the exit latencies using the SET_SEL request before device initiated link powermanagement can be enabled. The exit latency values do not change after enumeration, it's enough to set them once. So do like Windows 10 and issue the SET_SEL request once just before setting the configuration. This is also the sequence described in USB 3.2 specs "9.1.2 Bus enumeration". SET_SEL is issued once before the Set Configuration request, and won't be cleared by the Set Configuration, Set Interface or ClearFeature (STALL) requests. Only warm reset, hot reset, set Address 0 clears the exit latencies. See USB 3.2 section 9.4.14 Table 9-10 Device parameters and events Add udev->lpm_devinit_allow, and set it if SET_SEL was successful. If not set, then don't try to enable device initiated LPM We used to issue a SET_SEL request every time lpm is enabled for either U1 or U2 link states, meaning a SET_SEL was issued twice after every Set Configuration and Set Interface requests, easily accumulating to over 15 SET_SEL requets during a USB3 webcam enumeration. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20220506161807.3369439-1-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.