[PATCH v2] PCI/DPC: Increase recovery timeout to 60 seconds

[PATCH v2] PCI/DPC: Increase recovery timeout to 60 seconds

[Ziyou Wang (Lenovo)]

Some NVMe devices need more than 5 seconds to recover after DPC
containment, but pci_dpc_recovered() waits only 4 seconds.  If the device
hasn't recovered by then, pciehp reports "device recovery failed" and
the device is re-enumerated.

Move PCIE_RESET_READY_POLL_MS definition from pci.c to pci.h so it can be
used in dpc.c.  Use PCIE_RESET_READY_POLL_MS (60 seconds) as the timeout
so pciehp waits as long as pci_dev_wait() does, which is sufficient for
all known devices.

Tested with INNOGRIT NVMe SSD [1dbe:5668] with ACS Fatal error
injection:

Upstream kernel (7.3.0-master+, 4s timeout):
  [123.018691] nvme: not ready 1023ms after DPC; waiting
  [124.106690] nvme: not ready 2047ms after DPC; waiting
  [125.642703] pciehp: Slot(64): Link Down
  [126.218696] AER: subordinate device reset failed
  [126.218700] AER: device recovery failed
  Device re-enumerated as nvme1

With this patch (60s timeout):
  [74.894811] nvme: not ready 1023ms after DPC; waiting
  [75.982813] nvme: not ready 2047ms after DPC; waiting
  [78.094810] nvme: ready 4095ms after DPC
  [78.094816] nvme: restart after slot reset
  [78.111620] AER: device recovery successful
  Device works normally

Fixes: a97396c6eb13 ("PCI: pciehp: Ignore Link Down/Up caused by DPC")
Cc: stable@vger.kernel.org
Signed-off-by: Ziyou Wang (Lenovo) <ziyou.dev@foxmail.com>
---
 drivers/pci/pci.c      |  1 -
 drivers/pci/pci.h      | 10 ++++++++++
 drivers/pci/pcie/dpc.c | 11 ++++++-----
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8cc6a89130b5..08f08f25e597 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -80,7 +80,6 @@ struct pci_pme_device {
  * limit, but 60 sec ought to be enough for any device to become
  * responsive.
  */
-#define PCIE_RESET_READY_POLL_MS 60000 /* msec */
 
 static void pci_dev_d3_sleep(struct pci_dev *dev)
 {
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index ba3c3fddddc2..1e8ddcc013ff 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -61,6 +61,16 @@ struct pcie_tlp_log;
  */
 #define PCIE_RESET_CONFIG_WAIT_MS	100
 
+/*
+ * Time to wait for a device to become ready after a reset.
+ *
+ * Devices may extend the 1 sec period through Request Retry Status
+ * completions (PCIe r6.0 sec 2.3.1).  The spec does not provide an upper
+ * limit, but 60 sec ought to be enough for any device to become
+ * responsive.
+ */
+#define PCIE_RESET_READY_POLL_MS	60000	/* msec */
+
 /* Parameters for the waiting for link up routine */
 #define PCIE_LINK_WAIT_MAX_RETRIES	10
 #define PCIE_LINK_WAIT_SLEEP_MS		90
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 2b779bd1d861..df1c469fa24c 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -116,12 +116,13 @@ bool pci_dpc_recovered(struct pci_dev *pdev)
 		return false;
 
 	/*
-	 * Need a timeout in case DPC never completes due to failure of
-	 * dpc_wait_rp_inactive().  The spec doesn't mandate a time limit,
-	 * but reports indicate that DPC completes within 4 seconds.
+	 * Wait for DPC recovery completion.  Use PCIE_RESET_READY_POLL_MS
+	 * (60s) to match pci_dev_wait() timeout.  Some devices need >5 seconds
+	 * to recover after DPC containment.  The 4 second timeout is too short.
 	 */
-	wait_event_timeout(dpc_completed_waitqueue, dpc_completed(pdev),
-			   msecs_to_jiffies(4000));
+	wait_event_timeout(dpc_completed_waitqueue,
+			   dpc_completed(pdev),
+			   msecs_to_jiffies(PCIE_RESET_READY_POLL_MS));
 
 	return test_and_clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
 }
-- 
2.53.0

Re: [PATCH v2] PCI/DPC: Increase recovery timeout to 60 seconds

[Bjorn Helgaas]

On Fri, Nov 06, 2026 at 04:56:55PM +0800, Ziyou Wang (Lenovo) wrote:
> Some NVMe devices need more than 5 seconds to recover after DPC
> containment, but pci_dpc_recovered() waits only 4 seconds.  If the device
> hasn't recovered by then, pciehp reports "device recovery failed" and
> the device is re-enumerated.
> 
> Move PCIE_RESET_READY_POLL_MS definition from pci.c to pci.h so it can be
> used in dpc.c.  Use PCIE_RESET_READY_POLL_MS (60 seconds) as the timeout
> so pciehp waits as long as pci_dev_wait() does, which is sufficient for
> all known devices.
> 
> Tested with INNOGRIT NVMe SSD [1dbe:5668] with ACS Fatal error
> injection:
> 
> Upstream kernel (7.3.0-master+, 4s timeout):
>   [123.018691] nvme: not ready 1023ms after DPC; waiting
>   [124.106690] nvme: not ready 2047ms after DPC; waiting

Was there a "not ready ... after DPC; giving up" message here?
pci_dev_wait() should log *something* about how it resolved this
situation.

>   [125.642703] pciehp: Slot(64): Link Down
>   [126.218696] AER: subordinate device reset failed
>   [126.218700] AER: device recovery failed
>   Device re-enumerated as nvme1
> 
> With this patch (60s timeout):
>   [74.894811] nvme: not ready 1023ms after DPC; waiting
>   [75.982813] nvme: not ready 2047ms after DPC; waiting
>   [78.094810] nvme: ready 4095ms after DPC
>   [78.094816] nvme: restart after slot reset
>   [78.111620] AER: device recovery successful
>   Device works normally
> 
> Fixes: a97396c6eb13 ("PCI: pciehp: Ignore Link Down/Up caused by DPC")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ziyou Wang (Lenovo) <ziyou.dev@foxmail.com>
> ---

30 minutes after v1 is too soon to post a v2.  A couple days is a
reasonable interval.

v2 should include a note here (after the "---") about what changed
since v1 and ideally a lore link to the v1 posting.