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527101ce6a
This patch (as1268) changes the way usbcore handles child devices that undergo a disconnection and reconnection while the parent hub is suspended. Currently, if the child isn't enabled for remote wakeup we leave it alone, figuring that it will go through a reset-resume when somebody tries to use it. However this isn't a good approach if the reason for the disconnection is that the child decided to switch modes or in some other way alter its descriptors. In that case we want to re-enumerate it as soon as possible, not wait until somebody forces a reset-resume. To resolve the issue, this patch treats reconnected suspended child devices as though they had requested a remote wakeup, even if they weren't enabled for it. The mode switch or descriptor change will be detected during the reset part of the reset-resume, and the device will be re-enumerated immediately. The disadvantage of this change is that it will cause autosuspended devices to be resumed when the computer wakes up from a system sleep during which the root hub was reset or lost power. This shouldn't matter much; some people would even argue that autosuspended devices should _always_ be resumed when the system wakes up! Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: "Yang Fei-AFY095" <fei.yang@motorola.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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| .. | ||
| atm | ||
| c67x00 | ||
| class | ||
| core | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| 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.