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

From: Gavin Shan <[email-masked]>
Date: Thu, 8 Oct 2015 10:20:14 +1100

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.

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
>