diff mbox series

PCI/AER: Block runtime suspend when handling errors

Message ID 20240209140841.1854711-1-stanislaw.gruszka@linux.intel.com
State Superseded
Headers show
Series PCI/AER: Block runtime suspend when handling errors | expand

Commit Message

Stanislaw Gruszka Feb. 9, 2024, 2:08 p.m. UTC
PM runtime can be done simultaneously with AER error handling.
Avoid that by using pm_runtime_get_sync() before and pm_runtime_put()
after reset in pcie_do_recovery() for all recovering devices.

pm_runtime_get_sync() will increase dev->power.usage_count counter
to prevent any possible future request to runtime suspend a device,
as well as resume device is was in D3hot state.

I tested with igc device by doing simultaneous aer_inject and
rpm suspend/resume via /sys/bus/pci/devices/PCI_ID/power/control
and can reproduce:

igc 0000:02:00.0: not ready 65535ms after bus reset; giving up
pcieport 0000:00:1c.2: AER: Root Port link has been reset (-25)
pcieport 0000:00:1c.2: AER: subordinate device reset failed
pcieport 0000:00:1c.2: AER: device recovery failed
igc 0000:02:00.0: Unable to change power state from D3hot to D0, device inaccessible

The problem disappears when applied this patch.

Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
---
RFC -> v1:
 add runtime callbacks to pcie_do_recovery(), this covers DPC case
 as well as case of recovering multiple devices under same port.
 
 drivers/pci/pcie/err.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Stanislaw Gruszka Feb. 12, 2024, 8:13 a.m. UTC | #1
On Fri, Feb 09, 2024 at 07:45:05AM -0800, Kuppuswamy Sathyanarayanan wrote:
> 
> On 2/9/24 6:08 AM, Stanislaw Gruszka wrote:
> > PM runtime can be done simultaneously with AER error handling.
> > Avoid that by using pm_runtime_get_sync() before and pm_runtime_put()
> > after reset in pcie_do_recovery() for all recovering devices.
> >
> > pm_runtime_get_sync() will increase dev->power.usage_count counter
> > to prevent any possible future request to runtime suspend a device,
> > as well as resume device is was in D3hot state.
> runtime suspend a device or resume a device that was in D3hot state.

I think "or" is not proper here, since both: resume and prevention
of suspend are done. I'll reword this way:

pm_runtime_get_sync() will increase dev->power.usage_count counter
to prevent any possible future request to runtime suspend a device
It will also resume a device, if it was previously in D3hot state. 

Hope that's clearer.

Thanks
Stanislaw
diff mbox series

Patch

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 59c90d04a609..705893b5f7b0 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -13,6 +13,7 @@ 
 #define dev_fmt(fmt) "AER: " fmt
 
 #include <linux/pci.h>
+#include <linux/pm_runtime.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
@@ -85,6 +86,18 @@  static int report_error_detected(struct pci_dev *dev,
 	return 0;
 }
 
+static int pci_pm_runtime_get_sync(struct pci_dev *pdev, void *data)
+{
+	pm_runtime_get_sync(&pdev->dev);
+	return 0;
+}
+
+static int pci_pm_runtime_put(struct pci_dev *pdev, void *data)
+{
+	pm_runtime_put(&pdev->dev);
+	return 0;
+}
+
 static int report_frozen_detected(struct pci_dev *dev, void *data)
 {
 	return report_error_detected(dev, pci_channel_io_frozen, data);
@@ -207,6 +220,8 @@  pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	else
 		bridge = pci_upstream_bridge(dev);
 
+	pci_walk_bridge(bridge, pci_pm_runtime_get_sync, NULL);
+
 	pci_dbg(bridge, "broadcast error_detected message\n");
 	if (state == pci_channel_io_frozen) {
 		pci_walk_bridge(bridge, report_frozen_detected, &status);
@@ -251,10 +266,15 @@  pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 		pcie_clear_device_status(dev);
 		pci_aer_clear_nonfatal_status(dev);
 	}
+
+	pci_walk_bridge(bridge, pci_pm_runtime_put, NULL);
+
 	pci_info(bridge, "device recovery successful\n");
 	return status;
 
 failed:
+	pci_walk_bridge(bridge, pci_pm_runtime_put, NULL);
+
 	pci_uevent_ers(bridge, PCI_ERS_RESULT_DISCONNECT);
 
 	/* TODO: Should kernel panic here? */