PCI/AER: Log which device prevents error recovery

PCI error recovery will fail if any device under the Root Port doesn't have
an error_detected callback.  Currently only the failure result is printed,
which is not enough to identify the driver that lacks the callback.

Log a message to identify the device with no error_detected callback.

[bhelgaas: tweak log message]
Link: https://lore.kernel.org/r/1576237474-32021-1-git-send-email-yangyicong@hisilicon.com
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pcie/err.c

@@ -61,10 +61,12 @@ static int report_error_detected(struct pci_dev *dev,
 		 * error callbacks of "any" device in the subtree, and will
 		 * exit in the disconnected error state.
 		 */
-		if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE)
+		if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
 			vote = PCI_ERS_RESULT_NO_AER_DRIVER;
-		else
+			pci_info(dev, "AER: Can't recover (no error_detected callback)\n");
+		} else {
 			vote = PCI_ERS_RESULT_NONE;
+		}
 	} else {
 		err_handler = dev->driver->err_handler;
 		vote = err_handler->error_detected(dev, state);