From: Sandeep Singh <Sandeep.Singh@amd.com>
To: gregkh@linuxfoundation.org, mathias.nyman@intel.com,
        ben@decadent.org.uk
Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        Sandeep Singh <sandeep.singh@amd.com>,
        Sandeep Singh <Sandeep.Singh@amd.com>,
        Shyam Sundar S K <Shyam-sundar.S-k@amd.com>,
        Nehal Shah <Nehal-bakulchandra.Shah@amd.com>
Subject: [PATCH] usb:xhci:Fix regression when ATI chipsets detected
Date: Wed, 23 Aug 2017 16:26:00 +0530
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From: Sandeep Singh <sandeep.singh@amd.com>

The following commit cause a regression on ATI chipsets.
'commit e788787ef4f9 ("usb:xhci:Add quirk for Certain
failing HP keyboard on reset after resume")'

This causes pinfo->smbus_dev to be wrongly set to NULL on
systems with the ATI chipset that this function checks for first.

Added conditional check for AMD chipsets to avoid the overwriting
pinfo->smbus_dev.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Sandeep Singh <Sandeep.Singh@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
cc: Nehal Shah <Nehal-bakulchandra.Shah@amd.com>
---
 drivers/usb/host/pci-quirks.c | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index 5f4ca78..58b9685 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -142,29 +142,30 @@ static int amd_chipset_sb_type_init(struct amd_chipset_info *pinfo)
 			pinfo->sb_type.gen = AMD_CHIPSET_SB700;
 		else if (rev >= 0x40 && rev <= 0x4f)
 			pinfo->sb_type.gen = AMD_CHIPSET_SB800;
-	}
-	pinfo->smbus_dev = pci_get_device(PCI_VENDOR_ID_AMD,
-					  0x145c, NULL);
-	if (pinfo->smbus_dev) {
-		pinfo->sb_type.gen = AMD_CHIPSET_TAISHAN;
 	} else {
 		pinfo->smbus_dev = pci_get_device(PCI_VENDOR_ID_AMD,
 				PCI_DEVICE_ID_AMD_HUDSON2_SMBUS, NULL);
 
-		if (!pinfo->smbus_dev) {
-			pinfo->sb_type.gen = NOT_AMD_CHIPSET;
-			return 0;
+		if (pinfo->smbus_dev) {
+			rev = pinfo->smbus_dev->revision;
+			if (rev >= 0x11 && rev <= 0x14)
+				pinfo->sb_type.gen = AMD_CHIPSET_HUDSON2;
+			else if (rev >= 0x15 && rev <= 0x18)
+				pinfo->sb_type.gen = AMD_CHIPSET_BOLTON;
+			else if (rev >= 0x39 && rev <= 0x3a)
+				pinfo->sb_type.gen = AMD_CHIPSET_YANGTZE;
+		} else {
+			pinfo->smbus_dev = pci_get_device(PCI_VENDOR_ID_AMD,
+							  0x145c, NULL);
+			if (pinfo->smbus_dev) {
+				rev = pinfo->smbus_dev->revision;
+				pinfo->sb_type.gen = AMD_CHIPSET_TAISHAN;
+			} else {
+				pinfo->sb_type.gen = NOT_AMD_CHIPSET;
+				return 0;
+			}
 		}
-
-		rev = pinfo->smbus_dev->revision;
-		if (rev >= 0x11 && rev <= 0x14)
-			pinfo->sb_type.gen = AMD_CHIPSET_HUDSON2;
-		else if (rev >= 0x15 && rev <= 0x18)
-			pinfo->sb_type.gen = AMD_CHIPSET_BOLTON;
-		else if (rev >= 0x39 && rev <= 0x3a)
-			pinfo->sb_type.gen = AMD_CHIPSET_YANGTZE;
 	}
-
 	pinfo->sb_type.rev = rev;
 	return 1;
 }
-- 
2.7.4