f7599be2bb
Currently ACPI power domain brings devices into D0 state in the "resume early" phase. Normally this does not cause any issues, as powering up happens quickly. However there are peripherals that have certain timing requirements for powering on, for example some models of Elan touchscreens need 300msec after powering up/releasing reset line before they can accept commands from the host. Such devices will dominate the time spent in early resume phase and cause increase in overall resume time as we wait for early resume to complete before we can proceed to the normal resume stage. There are ways for a driver to indicate that it can tolerate device being in the low power mode and that it knows how to power the device back up when resuming, bit that requires changes to individual drivers that may not really care about details of ACPI controlled power management. This change attempts to solve this issue at ACPI power domain level, by postponing powering up device until we get to the normal resume stage, unless there is early resume handler defined for the device, or device does not declare any resume handlers, in which case we continue powering up such devices early. This allows us to shave off several hundred milliseconds of resume time on affected systems. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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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.