[PATCH 1/3] drivers/pci/hotplug: Handle presence detection change properly

[PATCH 1/3] drivers/pci/hotplug: Handle presence detection change properly

[Gavin Shan]

The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
driver. In the interrupt handler, pnv_php_interrupt(), we bail when
pnv_pci_get_presence_state() returns zero wrongly. It causes the
presence change event is always ignored incorrectly.

This fixes the issue by bailing on error (non-zero value) returned
from pnv_pci_get_presence_state().

Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Cc: stable@vger.kernel.org #v4.9+
Reported-by: Hank Chang <hankmax0000@gmail.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: Willie Liauw <williel@supermicro.com.tw>
---
 drivers/pci/hotplug/pnv_php.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
index 56efaf7..306728c 100644
--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -707,8 +707,12 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data)
 		added = !!(lsts & PCI_EXP_LNKSTA_DLLLA);
 	} else if (sts & PCI_EXP_SLTSTA_PDC) {
 		ret = pnv_pci_get_presence_state(php_slot->id, &presence);
-		if (!ret)
+		if (ret) {
+			dev_warn(&pdev->dev, "PCI slot [%s] error %d getting presence (0x%04x), to retry the operation.\n",
+				 php_slot->name, ret, sts);
 			return IRQ_HANDLED;
+		}
+
 		added = !!(presence == OPAL_PCI_SLOT_PRESENT);
 	} else {
 		return IRQ_NONE;
-- 
2.7.4

[PATCH 2/3] drivers/pci/hotplug: Fix initial state for empty slot

[Gavin Shan]

In PowerNV PCI hotplug driver, the initial PCI slot's state is set
to PNV_PHP_STATE_POPULATED if no PCI devices are connected to the
slot. The PCI devices that are hot added to the slot won't be probed
and populated because of the check in pnv_php_enable():

        /* Check if the slot has been configured */
        if (php_slot->state != PNV_PHP_STATE_REGISTERED)
                return 0;

This fixes the issue by leaving the slot in PNV_PHP_STATE_REGISTERED
state initially if nothing is connected to the slot.

Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Cc: stable@vger.kernel.org #v4.9+
Reported-by: Hank Chang <hankmax0000@gmail.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: Willie Liauw <williel@supermicro.com.tw>
---
 drivers/pci/hotplug/pnv_php.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
index 306728c..41304b3 100644
--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -430,9 +430,21 @@ static int pnv_php_enable(struct pnv_php_slot *php_slot, bool rescan)
 	if (ret)
 		return ret;
 
-	/* Proceed if there have nothing behind the slot */
-	if (presence == OPAL_PCI_SLOT_EMPTY)
+	/*
+	 * Proceed if there have nothing behind the slot. However,
+	 * we should leave the slot in registered state at the
+	 * beginning. Otherwise, the PCI devices inserted afterwards
+	 * won't be probed and populated.
+	 */
+	if (presence == OPAL_PCI_SLOT_EMPTY) {
+		if (!php_slot->power_state_check) {
+			php_slot->power_state_check = true;
+
+			return 0;
+		}
+
 		goto scan;
+	}
 
 	/*
 	 * If the power supply to the slot is off, we can't detect
-- 
2.7.4

Re: [1/3] drivers/pci/hotplug: Handle presence detection change properly

[Michael Ellerman]

On Wed, 2017-01-11 at 00:50:06 UTC, Gavin Shan wrote:
> The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
> driver. In the interrupt handler, pnv_php_interrupt(), we bail when
> pnv_pci_get_presence_state() returns zero wrongly. It causes the
> presence change event is always ignored incorrectly.
> 
> This fixes the issue by bailing on error (non-zero value) returned
> from pnv_pci_get_presence_state().
> 
> Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
> Cc: stable@vger.kernel.org #v4.9+
> Reported-by: Hank Chang <hankmax0000@gmail.com>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> Tested-by: Willie Liauw <williel@supermicro.com.tw>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/d7d55536c6cd1f80295b6d7483ad05

cheers