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The following patch is required to resolve remote wake issues with certain devices. Issue description: If the remote wake is issued from the device in a specific timing condition while the system is entering sleep state then it may cause system to auto wake on subsequent sleep cycle. Root cause: Host controller rebroadcasts the Resume signal > 100 µseconds after receiving the original resume event from the device. For proper function, some devices may require the rebroadcast of resume event within the USB spec of 100µS. Workaroud: 1. Filter the AMD platforms with Yangtze chipset, then judge of all the usb devices are mouse or not. And get out the port id which attached a mouse with Pixart controller. 2. Then reset the port which attached issue device during system resume from S3. [Q] Why the special devices are only mice? Would high speed devices such as 3G modem or USB Bluetooth adapter trigger this issue? - Current this sensitivity is only confined to devices that use Pixart controllers. This controller is designed for use with LS mouse devices only. We have not observed any other devices failing. There may be a small risk for other devices also but this patch (reset device in resume phase) will cover the cases if required. [Q] Shouldn’t the resume signal be sent within 100 us for every device? - The Host controller may not send the resume signal within 100us, this our host controller specification change. This is why we require the patch to prevent side effects on certain known devices. [Q] Why would clicking mouse INTENSELY to wake the system up trigger this issue? - This behavior is specific to the devices that use Pixart controller. It is timing dependent on when the resume event is triggered during the sleep state. [Q] Is it a host controller issue or mouse? - It is the host controller behavior during resume that triggers the device incorrect behavior on the next resume. This patch sets USB_QUIRK_RESET_RESUME flag for these Pixart-based mice when they attached to platforms with AMD Yangtze chipset. Signed-off-by: Huang Rui <ray.huang@amd.com> Suggested-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.