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pnp: respect PNP_DRIVER_RES_DO_NOT_CHANGE when detaching

PATCH Applied Heiner Kallweit 2 participants 2 messages Dec 16, 2015 – Jan 5, 2016

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PATCH 1/1 pnp: respect PNP_DRIVER_RES_DO_NOT_CHANGE when detaching

I have a device (Nuvoton 6779D Super-IO IR RC with nuvoton-cir driver) which works after initial boot but not any longer if I unload and re-load the driver module.

Digging into the issue I found that unloading the driver calls pnp_disable_dev although the driver has flag PNP_DRIVER_RES_DO_NOT_CHANGE set. IMHO this is not right.

Let's have a look at the call chain when probing a device:
pnp_device_probe
1. attaches the device
2. if it's not active and PNP_DRIVER_RES_DO_NOT_CHANGE is not set it gets activated
3. probes driver

I think pnp_device_remove should do it in reverse order and also respect PNP_DRIVER_RES_DO_NOT_CHANGE. Therefore:
1. call drivers remove callback
2. if device is active and PNP_DRIVER_RES_DO_NOT_CHANGE is not set disable it
3. detach device

The change works for me and sounds logical to me. However I don't know the pnp driver in detail so I might be wrong.

---
 drivers/pnp/driver.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
drivers/pnp/driver.c +5 -1
index 153a493..74b201d 100644
@@ -74,7 +74,6 @@ void pnp_device_detach(struct pnp_dev *pnp_dev)
 	if (pnp_dev->status == PNP_ATTACHED)
 		pnp_dev->status = PNP_READY;
 	mutex_unlock(&pnp_lock);
-	pnp_disable_dev(pnp_dev);
 }
 
 static int pnp_device_probe(struct device *dev)
@@ -131,6 +130,11 @@ static int pnp_device_remove(struct device *dev)
 			drv->remove(pnp_dev);
 		pnp_dev->driver = NULL;
 	}
+
+	if (pnp_dev->active &&
+	    (!drv || !(drv->flags & PNP_DRIVER_RES_DO_NOT_CHANGE)))
+		pnp_disable_dev(pnp_dev);
+
 	pnp_device_detach(pnp_dev);
 	return 0;
 }
Signature · 1 line
2.6.2
#1 lore raw
Quoted 22 lines · Heiner Kallweit

I have a device (Nuvoton 6779D Super-IO IR RC with nuvoton-cir driver) which works after initial boot but not any longer if I unload and re-load the driver module.

Digging into the issue I found that unloading the driver calls pnp_disable_dev although the driver has flag PNP_DRIVER_RES_DO_NOT_CHANGE set. IMHO this is not right.

Let's have a look at the call chain when probing a device:
pnp_device_probe
1. attaches the device
2. if it's not active and PNP_DRIVER_RES_DO_NOT_CHANGE is not set it gets activated
3. probes driver

I think pnp_device_remove should do it in reverse order and also respect PNP_DRIVER_RES_DO_NOT_CHANGE. Therefore:
1. call drivers remove callback
2. if device is active and PNP_DRIVER_RES_DO_NOT_CHANGE is not set disable it
3. detach device

Quoted 4 lines

The change works for me and sounds logical to me. However I don't know the pnp driver in detail so I might be wrong.

Applied, thanks!

Rafael