From: Alan Stern Date: Fri, 16 Nov 2007 16:58:15 +0000 (-0500) Subject: USB: power-management documenation update X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3c886c50486cfbef2a2382b99bf4083a465c970a;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git USB: power-management documenation update This patch (as1014) was partly written by Tilman Schmidt. It clarifies the USB power-management documentation by explaining that when a disconnect occurs, a suspend method call might not be followed by either a resume or a reset_resume call. Signed-off-by: Alan Stern Signed-off-by: Tilman Schmidt Signed-off-by: Greg Kroah-Hartman --- diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt index 97842deec471..b2fc4d4a9917 100644 --- a/Documentation/usb/power-management.txt +++ b/Documentation/usb/power-management.txt @@ -278,6 +278,14 @@ optional. The methods' jobs are quite simple: (although the interfaces will be in the same altsettings as before the suspend). +If the device is disconnected or powered down while it is suspended, +the disconnect method will be called instead of the resume or +reset_resume method. This is also quite likely to happen when +waking up from hibernation, as many systems do not maintain suspend +current to the USB host controllers during hibernation. (It's +possible to work around the hibernation-forces-disconnect problem by +using the USB Persist facility.) + The reset_resume method is used by the USB Persist facility (see Documentation/usb/persist.txt) and it can also be used under certain circumstances when CONFIG_USB_PERSIST is not enabled. Currently, if a