From 882fa27f488ed3c4b67699d99e8c5ff64c7a9cd1 Mon Sep 17 00:00:00 2001 From: Chunfeng Yun Date: Tue, 26 Jan 2016 17:50:10 +0200 Subject: usb: xhci-mtk: fix AHB bus hang up caused by roothubs polling 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 Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- 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 c9ab6a44c34a..9532f5aef71b 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 fails, and all clocks are disabled, access register will hang + * AHB bus, so stop polling roothubs to avoid regs access on bus suspend. + * and no need to check whether ip sleep failed or not; this will cause SPM + * to wake up system immediately after system suspend complete if ip sleep + * fails, it is what we wanted. + */ static int xhci_mtk_suspend(struct device *dev) { struct xhci_hcd_mtk *mtk = dev_get_drvdata(dev); + struct usb_hcd *hcd = mtk->hcd; + struct xhci_hcd *xhci = hcd_to_xhci(hcd); + + xhci_dbg(xhci, "%s: stop port polling\n", __func__); + clear_bit(HCD_FLAG_POLL_RH, &hcd->flags); + del_timer_sync(&hcd->rh_timer); + clear_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags); + del_timer_sync(&xhci->shared_hcd->rh_timer); xhci_mtk_host_disable(mtk); xhci_mtk_phy_power_off(mtk); @@ -710,11 +725,19 @@ static int xhci_mtk_suspend(struct device *dev) static int xhci_mtk_resume(struct device *dev) { struct xhci_hcd_mtk *mtk = dev_get_drvdata(dev); + struct usb_hcd *hcd = mtk->hcd; + struct xhci_hcd *xhci = hcd_to_xhci(hcd); usb_wakeup_disable(mtk); xhci_mtk_clks_enable(mtk); xhci_mtk_phy_power_on(mtk); xhci_mtk_host_enable(mtk); + + xhci_dbg(xhci, "%s: restart port polling\n", __func__); + set_bit(HCD_FLAG_POLL_RH, &hcd->flags); + usb_hcd_poll_rh_status(hcd); + set_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags); + usb_hcd_poll_rh_status(xhci->shared_hcd); return 0; } -- cgit v1.2.3-59-g8ed1b