Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753399AbaKEDKm (ORCPT ); Tue, 4 Nov 2014 22:10:42 -0500 Received: from mga01.intel.com ([192.55.52.88]:23387 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753235AbaKEDKk (ORCPT ); Tue, 4 Nov 2014 22:10:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="411590402" Message-ID: <545994EA.6070300@linux.intel.com> Date: Wed, 05 Nov 2014 11:09:30 +0800 From: "Lu, Baolu" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-Version: 1.0 To: Alan Stern CC: Mathias Nyman , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/3] usb: xhci: This reworks ff8cbf250b448aac35589f6075082c3fcad8a8fe References: In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/5/2014 12:58 AM, Alan Stern wrote: > On Tue, 4 Nov 2014, Lu Baolu wrote: > >> xhci: clear root port wake on bits if controller isn't wake-up capable >> >> When system is being suspended, if host device is not wakeup capable, >> xhci_suspend() needs to clear all root port wake on bits. Otherwise, >> some platforms may generate spurious wakeup, even if PCI PME# is dis- >> abled. >> >> Signed-off-by: Lu Baolu >> --- >> drivers/usb/host/xhci.c | 42 ++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 42 insertions(+) >> >> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c >> index 2a5d45b..cd57aae 100644 >> --- a/drivers/usb/host/xhci.c >> +++ b/drivers/usb/host/xhci.c >> @@ -35,6 +35,8 @@ >> #define DRIVER_AUTHOR "Sarah Sharp" >> #define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver" >> >> +#define PORT_WAKE_BITS (PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E) >> + >> /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */ >> static int link_quirk; >> module_param(link_quirk, int, S_IRUGO | S_IWUSR); >> @@ -851,6 +853,42 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci) >> xhci_set_cmd_ring_deq(xhci); >> } >> >> +static void xhci_disable_port_wake_on_bits(struct xhci_hcd *xhci) >> +{ >> + int port_index; >> + __le32 __iomem **port_array; >> + unsigned long flags; >> + u32 t1, t2; >> + >> + spin_lock_irqsave(&xhci->lock, flags); >> + >> + /* disble usb3 ports Wake bits*/ >> + port_index = xhci->num_usb3_ports; >> + port_array = xhci->usb3_ports; >> + while (port_index--) { >> + t1 = readl(port_array[port_index]); >> + t2 = xhci_port_state_to_neutral(t1); >> + t2 &= ~PORT_WAKE_BITS; >> + t1 = xhci_port_state_to_neutral(t1); >> + if (t1 != t2) >> + writel(t2, port_array[port_index]); >> + } >> + >> + /* disble usb2 ports Wake bits*/ >> + port_index = xhci->num_usb2_ports; >> + port_array = xhci->usb2_ports; >> + while (port_index--) { >> + t1 = readl(port_array[port_index]); >> + t2 = xhci_port_state_to_neutral(t1); >> + t2 &= ~PORT_WAKE_BITS; >> + t1 = xhci_port_state_to_neutral(t1); >> + if (t1 != t2) >> + writel(t2, port_array[port_index]); >> + } >> + >> + spin_unlock_irqrestore(&xhci->lock, flags); >> +} >> + >> /* >> * Stop HC (not bus-specific) >> * >> @@ -868,6 +906,10 @@ int xhci_suspend(struct xhci_hcd *xhci) >> xhci->shared_hcd->state != HC_STATE_SUSPENDED) >> return -EINVAL; >> >> + /* Clear root port wake on bits if not wakeup capable. */ >> + if (!device_may_wakeup(hcd->self.controller)) >> + xhci_disable_port_wake_on_bits(xhci); >> + >> /* Don't poll the roothubs on bus suspend. */ >> xhci_dbg(xhci, "%s: stopping port polling.\n", __func__); >> clear_bit(HCD_FLAG_POLL_RH, &hcd->flags); > This is better but still wrong. Remember, this same code gets called > for system suspend _and_ for runtime suspend. During runtime suspend, > wakeup is always supposed to be turned on, even if device_may_wakeup() > is false. That's because device_may_wakeup() refers only to system > suspend. What you need to test is the do_wakeup flag, which should be > passed into xhci_suspend() by xhci_pci_suspend() and > xhci_plat_suspend(). Yes, it should cover runtime suspend as well. Thanks for the comments. I will resend the patch. > Another problem is in the patch description and the comments. If > device_may_wakeup() returns false, it doesn't mean the controller isn't > wakeup-capable -- it means the controller isn't _allowed_ to wake up > the system. Those are two different things. Accept, I will change this in new patch version. > > Finally, the code in xhci_disable_port_wake_on_bits() looks a little > peculiar -- I'm not sure about all those calls to > xhci_port_state_to_neutral(). But I'm not an expert on that; Mathias > will have to advise on it. This part of code was written with reference to code in xhci-hub.c. Comments of xhci_port_state_to_neutral(): /* * Given a port state, this function returns a value that would result in the * port being in the same state, if the value was written to the port status * control register. * Save Read Only (RO) bits and save read/write bits where * writing a 0 clears the bit and writing a 1 sets the bit (RWS). * For all other types (RW1S, RW1CS, RW, and RZ), writing a '0' has no effect. */ This calculation is used to avoid side effect of changing other bit fields. Thanks, -baolu > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/