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>
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