[PATCH] pm: print name of failed suspend function

Print more diagnostic info to help identify the source of power management
suspend failures.

Example:

usb_hcd_pci_suspend(): pci_set_power_state+0x0/0x1af() returns -22
pci_device_suspend(): usb_hcd_pci_suspend+0x0/0x11b() returns -22
suspend_device(): pci_device_suspend+0x0/0x34() returns -22

Work-in-progress.  It needs lots more suspend_report_result() calls sprinkled
everywhere.

Cc: Patrick Mochel <mochel@digitalimplant.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@suspend2.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/base/power/suspend.c

@@ -10,6 +10,8 @@
 
 #include <linux/vt_kern.h>
 #include <linux/device.h>
+#include <linux/kallsyms.h>
+#include <linux/pm.h>
 #include "../base.h"
 #include "power.h"
 
@@ -58,6 +60,7 @@ int suspend_device(struct device * dev, pm_message_t state)
 	if (dev->bus && dev->bus->suspend && !dev->power.power_state.event) {
 		dev_dbg(dev, "suspending\n");
 		error = dev->bus->suspend(dev, state);
+		suspend_report_result(dev->bus->suspend, error);
 	}
 	up(&dev->sem);
 	return error;
@@ -169,3 +172,12 @@ int device_power_down(pm_message_t state)
 
 EXPORT_SYMBOL_GPL(device_power_down);
 
+void __suspend_report_result(const char *function, void *fn, int ret)
+{
+	if (ret) {
+		printk(KERN_ERR "%s(): ", function);
+		print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
+		printk("%d\n", ret);
+	}
+}
+EXPORT_SYMBOL_GPL(__suspend_report_result);

drivers/pci/pci-driver.c

@@ -271,10 +271,12 @@ static int pci_device_suspend(struct device * dev, pm_message_t state)
 	struct pci_driver * drv = pci_dev->driver;
 	int i = 0;
 
-	if (drv && drv->suspend)
+	if (drv && drv->suspend) {
 		i = drv->suspend(pci_dev, state);
-	else
+		suspend_report_result(drv->suspend, i);
+	} else {
 		pci_save_state(pci_dev);
+	}
 	return i;
 }
 

drivers/pci/pci.c

@@ -307,9 +307,11 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 	 * Can enter D0 from any state, but if we can only go deeper 
 	 * to sleep if we're already in a low power state
 	 */
-	if (state != PCI_D0 && dev->current_state > state)
+	if (state != PCI_D0 && dev->current_state > state) {
+		printk(KERN_ERR "%s(): %s: state=%d, current state=%d\n",
+			__FUNCTION__, pci_name(dev), state, dev->current_state);
 		return -EINVAL;
-	else if (dev->current_state == state) 
+	} else if (dev->current_state == state)
 		return 0;        /* we're already there */
 
 	/* find PCI PM capability in list */

drivers/usb/core/hcd-pci.c

@@ -213,11 +213,9 @@ int usb_hcd_pci_suspend (struct pci_dev *dev, pm_message_t message)
 
 	if (hcd->driver->suspend) {
 		retval = hcd->driver->suspend(hcd, message);
-		if (retval) {
-			dev_dbg (&dev->dev, "PCI pre-suspend fail, %d\n",
-				retval);
+		suspend_report_result(hcd->driver->suspend, retval);
+		if (retval)
 			goto done;
-		}
 	}
 	synchronize_irq(dev->irq);
 
@@ -263,6 +261,7 @@ int usb_hcd_pci_suspend (struct pci_dev *dev, pm_message_t message)
 		 * some device state (e.g. as part of clock reinit).
 		 */
 		retval = pci_set_power_state (dev, PCI_D3hot);
+		suspend_report_result(pci_set_power_state, retval);
 		if (retval == 0) {
 			int wake = device_can_wakeup(&hcd->self.root_hub->dev);
 

include/linux/pm.h

@@ -199,6 +199,12 @@ extern int device_suspend(pm_message_t state);
 
 extern int dpm_runtime_suspend(struct device *, pm_message_t);
 extern void dpm_runtime_resume(struct device *);
+extern void __suspend_report_result(const char *function, void *fn, int ret);
+
+#define suspend_report_result(fn, ret)					\
+	do {								\
+		__suspend_report_result(__FUNCTION__, fn, ret);		\
+	} while (0)
 
 #else /* !CONFIG_PM */
 
@@ -219,6 +225,8 @@ static inline void dpm_runtime_resume(struct device * dev)
 {
 }
 
+#define suspend_report_result(fn, ret) do { } while (0)
+
 #endif
 
 /* changes to device_may_wakeup take effect on the next pm state change.