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authorLan Tianyu <tianyu.lan@intel.com>2012-09-05 13:44:34 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-09-10 13:04:01 -0700
commit05f916894a692f0cc0973aef21521133623b21c0 (patch)
treee6de832d1a7ec2fe92235a2f1cd6e2e6c6d33ae7 /Documentation/trace/mmiotrace.txt
parentd557542421da643358201664903e67fd01dfca1a (diff)
usb/acpi: Store info on device removability.
In the upcoming USB port power off patches, we need to know whether a USB port can ever see a disconnect event. Often USB ports are internal to a system, and users can't disconnect USB devices from that port. Sometimes those ports will remain empty, because the OEM chose not to connect an internal USB device to that port. According to ACPI Spec 9.13, PLD indicates whether USB port is user visible and _UPC indicates whether a USB device can be connected to the USB port (we'll call this "connectible"). Here's a matrix of the possible combinations: Visible Connectible Name Example ------------------------------------------------------------------------- Yes No Unknown (Invalid state.) Yes Yes Hot-plug USB ports on the outside of a laptop. A user could freely connect and disconnect USB devices. No Yes Hard-wired A USB modem hard-wired to a port on the inside of a laptop. No No Not used The port is internal to the system and will remain empty. Represent each of these four states with an enum usb_port_connect_type. The four states are USB_PORT_CONNECT_TYPE_UNKNOWN, USB_PORT_CONNECT_TYPE_HOT_PLUG, USB_PORT_CONNECT_TYPE_HARD_WIRED, and USB_PORT_NOT_USED. When we get the USB port's acpi_handle, store the state in connect_type in struct usb_port. Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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