From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] usb: xhci-mtk: fix AHB bus hang up caused by roothubs polling Date: Fri, 4 Dec 2015 16:24:32 +0300 Message-ID: <56619410.4000705@cogentembedded.com> References: <1449196807-31785-1-git-send-email-chunfeng.yun@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1449196807-31785-1-git-send-email-chunfeng.yun-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Chunfeng Yun , Mathias Nyman Cc: Matthias Brugger , Felipe Balbi , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Daniel Kurtz , Greg Kroah-Hartman List-Id: linux-mediatek@lists.infradead.org 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 > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html