Per AHCI spec v1.3.1, "7.3 Native Hot Plug Support", once LPM is enabled hotplug support needs to be disabled. The LPM code always followed this and disabled the port when no drives were connected, but as more machines will be exposed to this code it might be an unexpected behavior to some users. Add a note to parameter documentation to explain the new behavior. Link: https://bugs.launchpad.net/bugs/1971576 Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> --- Documentation/admin-guide/kernel-parameters.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9e6bd212004d..4dcd9a3ba4a5 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -279,6 +279,13 @@ 3 => Medium power with Device Initiated PM enabled 4 => Minimum power + NOTE: Enabling LPM when no drive is connected will disable + the port which means hotplug will not work. + + If hotplug is an important use case, this can be modified + at runtime by changing + /sys/module/ahci/parameters/lpm_policy + ALSA [HW,ALSA] See Documentation/sound/alsa-configuration.rst -- 2.34.1
