mirror of https://gitee.com/openkylin/linux.git
9574323c39
This patch tests USB2 software LPM for a USB2 LPM-capable device. When a lpm-capable device is addressed, if the host also supports software LPM, apply a test by putting the device into L1 state and resume it to see if the device can do L1 suspend/resume successfully. If the device fails to enter L1 or resume from L1 state, it may not function normally and usbcore may disconnect and re-enumerate it. In this case, store the device's Vid and Pid information, make sure the host will not test LPM for it twice. The test result is per device/host. Some devices claim to be lpm-capable, but fail to enter L1 or resume. So the test is necessary. The xHCI 1.0 errata has modified the USB2.0 LPM implementation. It redefines the HIRD field to BESL, and adds another register Port Hardware LPM Control (PORTHLPMC). However, this should not affect the LPM behavior on xHC which does not implement 1.0 errata. USB2.0 LPM errata defines a new bit BESL in the device's USB 2.0 extension descriptor. If the device reports it uses BESL, driver should use BESL instead of HIRD for it. Signed-off-by: Andiry Xu <andiry.xu@amd.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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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 | ||
README
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.