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usb: dwc3: re-enable runtime PM after failed resume

PATCH In review Roy Luo 2 participants 2 messages Sep 13, 2024 – Sep 16, 2024

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Roy Luo

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#0 lore raw

PATCH v2 1/1 usb: dwc3: re-enable runtime PM after failed resume

When dwc3_resume_common() returns an error, runtime pm is left in suspended and disabled state in dwc3_resume(). Since the device is suspended, its parent devices (like the power domain or glue driver) could also be suspended and may have released resources that dwc requires. Consequently, calling dwc3_suspend_common() in this situation could result in attempts to access unclocked or unpowered registers.
To prevent these problems, runtime PM should always be re-enabled, even after failed resume attempts. This ensures that dwc3_suspend_common() is skipped in such cases.

Fixes 68c26fe58182 ("usb: dwc3: set pm runtime active before resume common")
---
 drivers/usb/dwc3/core.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
drivers/usb/dwc3/core.c +3 -5
index ccc3895dbd7f..4bd73b5fe41b 100644
@@ -2537,7 +2537,7 @@ static int dwc3_suspend(struct device *dev)
 static int dwc3_resume(struct device *dev)
 {
 	struct dwc3	*dwc = dev_get_drvdata(dev);
-	int		ret;
+	int		ret = 0;
 
 	pinctrl_pm_select_default_state(dev);
 
@@ -2545,14 +2545,12 @@ static int dwc3_resume(struct device *dev)
 	pm_runtime_set_active(dev);
 
 	ret = dwc3_resume_common(dwc, PMSG_RESUME);
-	if (ret) {
+	if (ret)
 		pm_runtime_set_suspended(dev);
-		return ret;
-	}
 
 	pm_runtime_enable(dev);
 
-	return 0;
+	return ret;
 }
 
 static void dwc3_complete(struct device *dev)

base-commit: ad618736883b8970f66af799e34007475fe33a68

Signature · 1 line
2.46.0.662.g92d0881bb0-goog
maintainer Acked-by on v2 1/1
#1 lore raw
Quoted 49 lines · Roy Luo

When dwc3_resume_common() returns an error, runtime pm is left in suspended and disabled state in dwc3_resume(). Since the device is suspended, its parent devices (like the power domain or glue driver) could also be suspended and may have released resources that dwc requires. Consequently, calling dwc3_suspend_common() in this situation could result in attempts to access unclocked or unpowered registers.
To prevent these problems, runtime PM should always be re-enabled, even after failed resume attempts. This ensures that dwc3_suspend_common() is skipped in such cases.

Fixes 68c26fe58182 ("usb: dwc3: set pm runtime active before resume common")
---
 drivers/usb/dwc3/core.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
drivers/usb/dwc3/core.c +3 -5
index ccc3895dbd7f..4bd73b5fe41b 100644
@@ -2537,7 +2537,7 @@ static int dwc3_suspend(struct device *dev)
 static int dwc3_resume(struct device *dev)
 {
 	struct dwc3	*dwc = dev_get_drvdata(dev);
-	int		ret;
+	int		ret = 0;
 
 	pinctrl_pm_select_default_state(dev);
 
@@ -2545,14 +2545,12 @@ static int dwc3_resume(struct device *dev)
 	pm_runtime_set_active(dev);
 
 	ret = dwc3_resume_common(dwc, PMSG_RESUME);
-	if (ret) {
+	if (ret)
 		pm_runtime_set_suspended(dev);
-		return ret;
-	}
 
 	pm_runtime_enable(dev);
 
-	return 0;
+	return ret;
 }
 
 static void dwc3_complete(struct device *dev)
Quoted 4 lines

base-commit: ad618736883b8970f66af799e34007475fe33a68

Signature · 1 line
2.46.0.662.g92d0881bb0-goog

Thanks,
Thinh