48fc7dbd52
Change the default enumeration scheme for xhci attached non-SuperSpeed devices from: Reset SetAddress [xhci address-device BSR = 0] GetDescriptor(8) GetDescriptor(18) ...to: Reset [xhci address-device BSR = 1] GetDescriptor(64) Reset SetAddress [xhci address-device BSR = 0] GetDescriptor(18) ...as some devices misbehave when encountering a SetAddress command prior to GetDescriptor. There are known legacy devices that require this scheme, but testing has found at least one USB3 device that fails enumeration when presented with this ordering. For now, follow the ehci case and enable 'new scheme' by default for non-SuperSpeed devices. To support this enumeration scheme on xhci the AddressDevice operation needs to be performed twice. The first instance of the command enables the HC's device and slot context info for the device, but omits sending the device a SetAddress command (BSR == block set address request). Then, after GetDescriptor completes, follow up with the full AddressDevice+SetAddress operation. As mentioned before, this ordering of events with USB3 devices causes an extra state transition to be exposed to xhci. Previously USB3 devices would transition directly from 'enabled' to 'addressed' and never need to underrun responses to 'get descriptor'. We do see the 64-byte descriptor fetch the correct data, but the following 18-byte descriptor read after the reset gets: bLength = 0 bDescriptorType = 0 bcdUSB = 0 bDeviceClass = 0 bDeviceSubClass = 0 bDeviceProtocol = 0 bMaxPacketSize0 = 9 instead of: bLength = 12 bDescriptorType = 1 bcdUSB = 300 bDeviceClass = 0 bDeviceSubClass = 0 bDeviceProtocol = 0 bMaxPacketSize0 = 9 which results in the discovery process looping until falling back to 'old scheme' enumeration. Acked-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: David Moore <david.moore@gmail.com> Suggested-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> |
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| .. | ||
| atm | ||
| c67x00 | ||
| chipidea | ||
| class | ||
| core | ||
| dwc3 | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| 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.