Commit e0f03e87 authored Dec 16, 2015 by Heiner Kallweit Committed by Rafael J. Wysocki Jan 04, 2016

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.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent a77060f0

drivers/pnp/driver.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}