Re: [RESEND PATCH v2] usb: xhci-mtk: fix AHB bus hang up caused by roothubs polling

From: Mathias Nyman
Date: Mon Jan 11 2016 - 08:56:20 EST


On 08.01.2016 03:28, Chunfeng Yun wrote:
when ip fails to enter sleep mode, register access protection will
be disabled, at the same time if all clocks are disabled, access
register will hang up AHB bus.
the common case causes ip sleep failure is that after all ports
enter U3 but before ip enters sleep mode, a port receives a resume
signal('K'). this will happens when such as clicks mouse to try to
do remote-wakeup to stop system enter suspend.
so stop polling root hubs to avoid access xHCI register on bus
suspend, and restart it when bus resumes.

Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
drivers/usb/host/xhci-mtk.c | 23 +++++++++++++++++++++++

The xhci Mediatek (xhci-mtk etc) support is in usb-next and should be available first time
in 4.5-rc1 kernel.

I'll forward fixes for it once 4.5-rc1 is out, they should end up in final 4.5

-Mathias