Re: [PATCH v3 3/3] driver-core: print bus registration error value

[Greg Kroah-Hartman]

On Tue, May 15, 2018 at 03:51:14PM +0200, Florian Schmaus wrote:
> Signed-off-by: Florian Schmaus <flo@xxxxxxxxxxxx>
> ---
>  drivers/base/driver.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/driver.c b/drivers/base/driver.c
> index afd5b08b7677..c68d35139c0f 100644
> --- a/drivers/base/driver.c
> +++ b/drivers/base/driver.c
> @@ -149,8 +149,9 @@ int driver_register(struct device_driver *drv)
>  	struct device_driver *other;
>  
>  	if (!drv->bus->p) {
> -		printk(KERN_ERR "Driver '%s' was unable to register bus_type\n",
> -			   drv->name);
> +		printk(KERN_ERR "Driver '%s' was unable to register bus_type "
> +			   "(error: %d)\n",
> +			   drv->name, drv->bus->bus_register_retval);

I don't understand, if a bus was never registered, this is going to fail
in lots of odd ways, including the value being 0, so that would show "no
error"?  Is this really needed?

A better message would be something like:
	"Driver '%s" was unable to register with bus_type '%s' because it was not initialized."

right?

thanks,

greg k-h