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

From: [email-masked] (Mathias Nyman)
Date: Mon, 11 Jan 2016 16:01:44 +0200

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 <[email-masked]>
> ---
>   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