Messages in this thread Patch in this message | | | Subject | Re: [PATCH] usb: xhci-mtk: fix AHB bus hang up caused by roothubs polling | From | Sergei Shtylyov <> | Date | Fri, 4 Dec 2015 16:24:32 +0300 |
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Hello.
Sorry for the grammar nitpicking but since it's in the comments, I felt the necessity to comment.
On 12/4/2015 5:40 AM, Chunfeng Yun wrote:
> when ip fail to enter sleep mode, register access protection will
Fails.
> be disabed, at the same time if all clocks are disabled, access ^^^^^^^ disabled
> register will hang up AHB bus. > the common case causes ip sleep fail is that after all ports enter
Failure.
> 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.
Wake up.
> so stop polling roothubs to avoid access xHCI register on bus
Root hubs. Accessing.
> suspend, and restart it when bus resume.
Resumes. Or "is resumed", maybe?
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> > --- > drivers/usb/host/xhci-mtk.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c > index c9ab6a4..38635fb 100644 > --- a/drivers/usb/host/xhci-mtk.c > +++ b/drivers/usb/host/xhci-mtk.c > @@ -696,9 +696,24 @@ static int xhci_mtk_remove(struct platform_device *dev) > } > > #ifdef CONFIG_PM_SLEEP > +/* > + * if ip sleep fail, and all clocks are disabled, access register will hang
Fails.
> + * AHB bus, so stop poll roothubs to avoid regs access on bus suspend.
Polling.
> + * and no need to check whether ip sleep fail or not; this will cause SPM to
Failed.
> + * wakeup system immediately after system suspend complete if ip sleep
Wake up.
> + * fail, it is what we wanted.
Fails.
> + */ [...]
MBR, Sergei
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