linux-kernel - [PATCH 3.16 06/83] usb: pci-quirks: Correct AMD PLL quirk detection

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Message-ID: <lsq.1574264230.906506239@decadent.org.uk>
Date:   Wed, 20 Nov 2019 15:37:16 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        "Ryan Kennedy" <ryan5544@...il.com>,
        "Alan Stern" <stern@...land.harvard.edu>
Subject: [PATCH 3.16 06/83] usb: pci-quirks: Correct AMD PLL quirk detection

3.16.78-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ryan Kennedy <ryan5544@...il.com>

commit f3dccdaade4118070a3a47bef6b18321431f9ac6 upstream.

The AMD PLL USB quirk is incorrectly enabled on newer Ryzen
chipsets. The logic in usb_amd_find_chipset_info currently checks
for unaffected chipsets rather than affected ones. This broke
once a new chipset was added in e788787ef. It makes more sense
to reverse the logic so it won't need to be updated as new
chipsets are added. Note that the core of the workaround in
usb_amd_quirk_pll does correctly check the chipset.

Signed-off-by: Ryan Kennedy <ryan5544@...il.com>
Fixes: e788787ef4f9 ("usb:xhci:Add quirk for Certain failing HP keyboard on reset after resume")
Acked-by: Alan Stern <stern@...land.harvard.edu>
Link: https://lore.kernel.org/r/20190704153529.9429-2-ryan5544@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/usb/host/pci-quirks.c | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -188,7 +188,7 @@ int usb_amd_find_chipset_info(void)
 {
 	unsigned long flags;
 	struct amd_chipset_info info;
-	int ret;
+	int need_pll_quirk = 0;
 
 	spin_lock_irqsave(&amd_lock, flags);
 
@@ -202,21 +202,28 @@ int usb_amd_find_chipset_info(void)
 	spin_unlock_irqrestore(&amd_lock, flags);
 
 	if (!amd_chipset_sb_type_init(&info)) {
-		ret = 0;
 		goto commit;
 	}
 
-	/* Below chipset generations needn't enable AMD PLL quirk */
-	if (info.sb_type.gen == AMD_CHIPSET_UNKNOWN ||
-			info.sb_type.gen == AMD_CHIPSET_SB600 ||
-			info.sb_type.gen == AMD_CHIPSET_YANGTZE ||
-			(info.sb_type.gen == AMD_CHIPSET_SB700 &&
-			info.sb_type.rev > 0x3b)) {
+	switch (info.sb_type.gen) {
+	case AMD_CHIPSET_SB700:
+		need_pll_quirk = info.sb_type.rev <= 0x3B;
+		break;
+	case AMD_CHIPSET_SB800:
+	case AMD_CHIPSET_HUDSON2:
+	case AMD_CHIPSET_BOLTON:
+		need_pll_quirk = 1;
+		break;
+	default:
+		need_pll_quirk = 0;
+		break;
+	}
+
+	if (!need_pll_quirk) {
 		if (info.smbus_dev) {
 			pci_dev_put(info.smbus_dev);
 			info.smbus_dev = NULL;
 		}
-		ret = 0;
 		goto commit;
 	}
 
@@ -235,7 +242,7 @@ int usb_amd_find_chipset_info(void)
 		}
 	}
 
-	ret = info.probe_result = 1;
+	need_pll_quirk = info.probe_result = 1;
 	printk(KERN_DEBUG "QUIRK: Enable AMD PLL fix\n");
 
 commit:
@@ -246,7 +253,7 @@ commit:
 
 		/* Mark that we where here */
 		amd_chipset.probe_count++;
-		ret = amd_chipset.probe_result;
+		need_pll_quirk = amd_chipset.probe_result;
 
 		spin_unlock_irqrestore(&amd_lock, flags);
 
@@ -262,7 +269,7 @@ commit:
 		spin_unlock_irqrestore(&amd_lock, flags);
 	}
 
-	return ret;
+	return need_pll_quirk;
 }
 EXPORT_SYMBOL_GPL(usb_amd_find_chipset_info);