Re: [PATCH] Bugfix: powerpc/eeh: Create eeh sysfs entry in post_init()

On Wed, Jun 25, 2014 at 02:23:53PM +0800, Wei Yang wrote:

On Wed, Jun 25, 2014 at 03:33:12PM +1000, Gavin Shan wrote:

quoted

On Tue, Jun 24, 2014 at 11:32:07PM -0400, Mike Qiu wrote:

[ cc Richard ]

quoted

Eeh sysfs entry created must be after EEH_ENABLED been set
in eeh_subsystem_flags.

In PowerNV platform, it try to create sysfs entry before
EEH_ENABLED been set, when boot up. So nothing will be
created for eeh in sysfs.

Could you please make the commit log more clear? :-)

I guess the issue is introduced by commit 2213fb1 ("
powerpc/eeh: Skip eeh sysfs when eeh is disabled"). The
commit checks EEH is enabled while creating PCI device
EEH sysfs files. If not, the sysfs files won't be created.
That's to avoid warning reported during PCI hotplug.

The problem you're reporting (if I understand completely):
You don't see the sysfs files after the system boots up.
If it's the case, you probably need following changes in
arch/powerpc/platforms/powernv/pci.c::pnv_pci_ioda_fixup().
Could you have a try with it?

#ifdef CONFIG_EEH
eeh_probe_mode_set(EEH_PROBE_MODE_DEV);
-	eeh_addr_cache_build();
eeh_init();
+	eeh_addr_cache_build();
#endif

I think this is a more proper fix.

BTW, I have one confusion in this mode set.

eeh_init()
 -> eeh_ops->dev_probe()
    -> powernv_eeh_dev_probe()
       -> eeh_set_enable(true)   <- here the eeh is marked enabled

We can see this flag would be set for each pci_dev. So is it possible to make
this "set" only once?

It shouldn't be a problem because there might not have PCI devices
supporting EEH in the guest. All PCI devices are emulated.

quoted

Eventually PowerNV/pSeries have same function call sequence:

- Set EEH probe mode
- Doing probe (with device node or PCI device)
- Build address cache.

quoted

Signed-off-by: Mike Qiu <redacted>
---
arch/powerpc/platforms/powernv/eeh-ioda.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/eeh-ioda.c b/arch/powerpc/platforms/powernv/eeh-ioda.c
index 8ad0c5b..5f95581 100644
--- a/arch/powerpc/platforms/powernv/eeh-ioda.c
+++ b/arch/powerpc/platforms/powernv/eeh-ioda.c

@@ -136,6 +136,9 @@ static int ioda_eeh_post_init(struct pci_controller *hose)

	struct pnv_phb *phb = hose->private_data;
	int ret;

+	/* Creat sysfs after EEH_ENABLED been set */
+	eeh_add_sysfs_files(hose->bus);
+
	/* Register OPAL event notifier */
	if (!ioda_eeh_nb_init) {
		ret = opal_notifier_register(&ioda_eeh_nb);

Thanks,
Gavin