forked from Minki/linux
72937e1e34
This patch takes care of the race condition between the Function Wake Device Notification and the auto-suspend timeout for this situation: Roothub | (U3) hub A | (U3) hub B | (U3) device C When device C signals a resume, the xHCI driver will set the wakeup_bits for the roothub port that hub A is attached to. However, since USB 3.0 hubs do not set a link state change bit on device-initiated resume, hub A will not indicate a port event when polled. Without this patch, khubd will notice the wakeup-bits are set for the roothub port, it will resume hub A, and then it will poll the events bits for hub A and notice that nothing has changed. Then it will be suspended after 2 seconds. Change hub_activate() to look at the port link state for each USB 3.0 hub port, and set hub->change_bits if the link state is U0, indicating the device has finished resume. Change the resume function called by hub_events(), hub_handle_remote_wakeup(), to check the link status for resume instead of just the port's wakeup_bits. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> |
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| atm | ||
| c67x00 | ||
| class | ||
| core | ||
| dwc3 | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| renesas_usbhs | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| usb-common.c | ||
| usb-skeleton.c | ||
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.