On Tue, Sep 29, 2015 at 11:10:39AM +0200, Tomeu Vizoso wrote:
> Lets implementations of the match() callback in struct bus_type to
> return errors and if it's -EPROBE_DEFER then queue the device for
> deferred probing.
>
> This is useful to buses such as AMBA in which devices are registered
> before their matching information can be retrieved from the HW
> (typically because a clock driver hasn't probed yet).
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
> ---
>
>
> drivers/base/dd.c | 24 ++++++++++++++++++++++--
> include/linux/device.h | 2 +-
> 2 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index be0eb4639128..7dc04ee81c8b 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -488,6 +488,7 @@ static int __device_attach_driver(struct device_driver *drv, void *_data)
> struct device_attach_data *data = _data;
> struct device *dev = data->dev;
> bool async_allowed;
> + int ret;
>
> /*
> * Check if device has already been claimed. This may
> @@ -498,8 +499,17 @@ static int __device_attach_driver(struct device_driver *drv, void *_data)
> if (dev->driver)
> return -EBUSY;
>
> - if (!driver_match_device(drv, dev))
> + ret = driver_match_device(drv, dev);
> + if (!ret)
> return 0;
> + else if (ret < 0) {
> + if (ret == -EPROBE_DEFER) {
> + dev_dbg(dev, "Device match requests probe deferral\n");
> + driver_deferred_probe_add(dev);
> + } else
> + dev_warn(dev, "Bus failed to match device: %d", ret);
This is going to start to cause warnings where there were previously
none, which isn't going to be a good idea. It's completly normal for a
bus to not match a device, let's not be noisy for no good reason, unless
you are going to deal with all of the confused user emails?
You do this a bunch in this patch, please don't.
thanks,
greg k-h
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