linux-kernel - [PATCH v4 6/8] pciehp: Disabling the link notification across slot reset

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Message-ID: <52F1A250.6030808@gmail.com>
Date:	Tue, 04 Feb 2014 18:30:40 -0800
From:	Rajat Jain <rajatxjain@...il.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>,
	Alex Williamson <alex.williamson@...hat.com>,
	Yijing Wang <wangyijing@...wei.com>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, Yinghai Lu <yhlu.kernel@...il.com>
CC:	Guenter Roeck <groeck@...iper.net>,
	Rajat Jain <rajatjain@...iper.net>,
	Rajat Jain <rajatxjain@...il.com>
Subject: [PATCH v4 6/8] pciehp: Disabling the link notification across slot
 reset

Disable the link notification (in addition to presence detect
notifications) across the slot reset since it could potentialy flap
the link and we don't want to treat it as hot unplug followed by a
hotplug.

Signed-off-by: Rajat Jain <rajatxjain@...il.com>
Signed-off-by: Rajat Jain <rajatjain@...iper.net>
Signed-off-by: Guenter Roeck <groeck@...iper.net>
---
 drivers/pci/hotplug/pciehp_hpc.c |   30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 15ca3a1..6433e73 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -619,33 +619,37 @@ static void pcie_disable_notification(struct controller *ctrl)
 
 /*
  * pciehp has a 1:1 bus:slot relationship so we ultimately want a secondary
- * bus reset of the bridge, but if the slot supports surprise removal we need
- * to disable presence detection around the bus reset and clear any spurious
+ * bus reset of the bridge, but if the slot supports surprise removal (or
+ * link state change based hotplug), we need to disable presence detection
+ * (or link state notifications) around the bus reset and clear any spurious
  * events after.
  */
 int pciehp_reset_slot(struct slot *slot, int probe)
 {
 	struct controller *ctrl = slot->ctrl;
 	struct pci_dev *pdev = ctrl_dev(ctrl);
+	u16 stat_mask = 0, ctrl_mask = 0;
 
 	if (probe)
 		return 0;
 
-	if (HP_SUPR_RM(ctrl)) {
-		pcie_write_cmd(ctrl, 0, PCI_EXP_SLTCTL_PDCE);
-		if (pciehp_poll_mode)
-			del_timer_sync(&ctrl->poll_timer);
+	if (HP_SUPR_RM(ctrl) && !ATTN_BUTTN(ctrl)) {
+		ctrl_mask |= PCI_EXP_SLTCTL_PDCE;
+		stat_mask |= PCI_EXP_SLTSTA_PDC;
 	}
+	ctrl_mask |= PCI_EXP_SLTCTL_DLLSCE;
+	stat_mask |= PCI_EXP_SLTSTA_DLLSC;
+
+	pcie_write_cmd(ctrl, 0, ctrl_mask);
+	if (pciehp_poll_mode)
+		del_timer_sync(&ctrl->poll_timer);
 
 	pci_reset_bridge_secondary_bus(ctrl->pcie->port);
 
-	if (HP_SUPR_RM(ctrl)) {
-		pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
-					   PCI_EXP_SLTSTA_PDC);
-		pcie_write_cmd(ctrl, PCI_EXP_SLTCTL_PDCE, PCI_EXP_SLTCTL_PDCE);
-		if (pciehp_poll_mode)
-			int_poll_timeout(ctrl->poll_timer.data);
-	}
+	pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, stat_mask);
+	pcie_write_cmd(ctrl, ctrl_mask, ctrl_mask);
+	if (pciehp_poll_mode)
+		int_poll_timeout(ctrl->poll_timer.data);
 
 	return 0;
 }
-- 
1.7.9.5

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