Subject: Re: [PATCH 1/5] powerpc/eeh: Don't unfreeze PHB PE after reset

From: Gavin Shan <[email-masked]>
Date: Thu, 8 Oct 2015 15:05:52 +1100

On Thu, Oct 08, 2015 at 10:20:14AM +1100, Gavin Shan wrote:
>On Wed, Oct 07, 2015 at 02:12:05PM +1100, Gavin Shan wrote:
>>On PowerNV platform, the PE is kept in frozen state until the PE
>>reset is completed to avoid recursive EEH error caused by MMIO
>>access during the period of EEH reset. The PE's frozen state is
>>cleared after BARs of PCI device included in the PE are restored
>>and enabled. However, we needn't clear the frozen state for PHB PE
>>explicitly at this point as there is no real PE for PHB PE. As the
>>PHB PE is always binding with PE#0, we actually clear PE#0, which
>>is wrong. It doesn't incur any problem though.
>>
>>This checks if the PE is PHB PE and doesn't clear the frozen state
>>if it is.
>>
>>Signed-off-by: Gavin Shan <[email-masked]>
>
>Michael, please ignore this series for now. One or two patches are
>still missed. Also, this series needs respin.
>

v2 was just sent out. Please look at v2 instead of this one.

Thanks,
Gavin

>>---
>> arch/powerpc/kernel/eeh_driver.c | 14 ++++++++++----
>> 1 file changed, 10 insertions(+), 4 deletions(-)
>>
>>diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
>>index 89eb4bc..3a626ed 100644
>>--- a/arch/powerpc/kernel/eeh_driver.c
>>+++ b/arch/powerpc/kernel/eeh_driver.c
>>@@ -587,10 +587,16 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
>> 	eeh_ops->configure_bridge(pe);
>> 	eeh_pe_restore_bars(pe);
>>
>>-	/* Clear frozen state */
>>-	rc = eeh_clear_pe_frozen_state(pe, false);
>>-	if (rc)
>>-		return rc;
>>+	/*
>>+	 * If it's PHB PE, the frozen state on all available PEs should have
>>+	 * been cleared by the PHB reset. Otherwise, we unfreeze the PE and its
>>+	 * child PEs because they might be in frozen state.
>>+	 */
>>+	if (!(pe->type & EEH_PE_PHB)) {
>>+		rc = eeh_clear_pe_frozen_state(pe, false);
>>+		if (rc)
>>+			return rc;
>>+	}
>>
>> 	/* Give the system 5 seconds to finish running the user-space
>> 	 * hotplug shutdown scripts, e.g. ifdown for ethernet.  Yes,
>>-- 
>>2.1.0
>>