linux-kernel - [PATCH] usb: host: ehci: workaround PME bug on AMD EHCI controller

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Message-Id: <20170609072233.5594-1-kai.heng.feng@canonical.com>
Date:   Fri,  9 Jun 2017 15:22:33 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     stern@...land.harvard.edu
Cc:     gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Kai-Heng Feng <kai.heng.feng@...onical.com>
Subject: [PATCH] usb: host: ehci: workaround PME bug on AMD EHCI controller

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 <kai.heng.feng@...onical.com>
---
 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:
-- 
2.13.0