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439d47608b
Commitaffccb16c1("ata: ahci: print the lpm policy on boot") added a lpm-pol print during boot, which shows the LPM policy used by each port. While the LPM policy is usually determined by the Kconfig CONFIG_SATA_MOBILE_LPM_POLICY, the Kconfig value is overridden e.g. if firmware has marked the port as hotplug capable / external. Commitf97106b10d("ata: ahci: Add debug print for external port") did add a debug print to show if LPM was disabled because firmware has marked the port as external, however, because devices having broken LPM (even though they claim to support it) is more common than one would have hoped, print "ext" during boot if firmware has marked the port is external. This will make it easier to debug certain LPM issues, e.g. if firmware has enabled/marked only some of the ports as hotplug capable / external. Before (port marked as external by firmware): ata1: SATA max UDMA/133 abar m4096@0xfebd3000 port 0xfebd3100 irq 57 lpm-pol 0 After (port marked as external by firmware): ata1: SATA max UDMA/133 abar m4096@0xfebd3000 port 0xfebd3100 irq 57 lpm-pol 0 ext Signed-off-by: Niklas Cassel <cassel@kernel.org> Signed-off-by: Damien Le Moal <dlemoal@kernel.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.