Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751595AbdFIOnq (ORCPT ); Fri, 9 Jun 2017 10:43:46 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:59568 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751527AbdFIOnp (ORCPT ); Fri, 9 Jun 2017 10:43:45 -0400 Date: Fri, 9 Jun 2017 10:43:43 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Kai-Heng Feng cc: gregkh@linuxfoundation.org, , Subject: Re: [PATCH] usb: host: ehci: workaround PME bug on AMD EHCI controller In-Reply-To: <20170609072233.5594-1-kai.heng.feng@canonical.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1400 Lines: 40 On Fri, 9 Jun 2017, Kai-Heng Feng wrote: > As Alan Stern points out [1], the PME signal is not enabled when > controller is in D3, therefore it's not being woken up when new deivces > get plugged in. > > Workaround this bug by preventing the controller enters D3 power state. > > [1] https://www.spinics.net/lists/linux-usb/msg157462.html > > Signed-off-by: Kai-Heng Feng > --- > drivers/usb/host/ehci-pci.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c > index 93326974ff4b..616685f83954 100644 > --- a/drivers/usb/host/ehci-pci.c > +++ b/drivers/usb/host/ehci-pci.c > @@ -181,6 +181,8 @@ static int ehci_pci_setup(struct usb_hcd *hcd) > if (pdev->device == 0x7808) { > ehci->use_dummy_qh = 1; > ehci_info(ehci, "applying AMD SB700/SB800/Hudson-2/3 EHCI dummy qh workaround\n"); > + > + pdev->dev_flags |= PCI_DEV_FLAGS_NO_D3; > } > break; > case PCI_VENDOR_ID_VIA: Is this really the right solution? Maybe it would be better to allow the controller to go into D3 provided no wakeup signal is needed. You could do: device_set_wakeup_capable(&pdev->dev, 0); Another alternative is to put the controller into D2 instead of D3, but (1) I don't know how to do that, and (2) we don't know if wakeup signalling works any better in D2 than it does in D3. Alan Stern