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| Filename | Latest commit message | Latest commit date |
|---|---|---|
It seems to be getting more common recently for EHCI host controllers to be probed after their companion UHCI or OHCI controllers. This may be caused partly by splitting the ehci-pci driver out from ehci-hcd, or it may be caused by changes in the way the kernel does driver probing. Regardless, it has a tendency to cause problems. When an EHCI controller is initialized, it takes ownership of all the ports away from the companions. In effect, it forcefully disconnects all the USB devices that may already be using a companion controller. This patch (as1672b) tries to make the transition more orderly by deconfiguring the root hubs for all the companion controllers before initializing the EHCI controller, and reconfiguring them afterward. The result is a soft disconnect rather than a hard one. Internally, the patch refactors the code involved in associating EHCI controllers with their companions. The old approach, in which a single function is called with an argument telling it what to do (the companion_action enum), has been replaced with a scheme using multiple callback functions, each performing a single task. This patch won't solve all the problems people encounter when their EHCI controllers start up, but it will at least reduce the number of error messages generated by the unexpected disconnections. Signed-off-by: Alan Stern <[email protected]> Tested-by: Jenya Y <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> |
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| atm | ||
| c67x00 | ||
| chipidea | ||
| class | ||
| core | ||
| dwc3 | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| phy | ||
| 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.