On Mon, 2014-04-28 at 00:01 +0200, Rafael J. Wysocki wrote:
> On Tuesday, April 08, 2014 12:06:49 AM Zhang Rui wrote:
> 
> [...]
> 
> > +
> > +static int acpi_pnp_scan_handler_attach(struct acpi_device *adev,
> > +                                   const struct acpi_device_id *id)
> > +{
> > +   return 1;
> > +}
> > +
> > +static int acpi_pnp_scan_handler_match(char *devid, char *handlerid)
> > +{
> > +   int i;
> > +
> > +   if (memcmp(devid, handlerid, 3))
> > +           return 0;
> > +
> > +   for (i = 3; i < 7; i++) {
> > +           /* Not a HEX value */
> > +           if (!((devid[i] >= '0' && devid[i] <= '9') ||
> > +                 (devid[i] > 'A' && devid[i] <= 'F')))
> > +                   return 0;
> > +
> > +           if ((handlerid[i] != 'X') &&
> 
> Hmm.  What exactly is the above check for?
> 
PNP bus supports wildcard in the drivers' id list.
say, drivers/tty/serial/8250/8250_pnp.c
      {"WACFXXX"},            /* Wacom tablets */
means the driver wants to try to probe all the PNP devices start with
"WACF".

thanks,
rui
> > +               toupper(devid[i]) != toupper(handlerid[i]))
> > +                   return 0;
> > +   }
> > +   return 1;
> > +}
> > +
> > +static struct acpi_scan_handler acpi_pnp_handler = {
> > +   .ids = acpi_pnp_device_ids,
> > +   .match = acpi_pnp_scan_handler_match,
> > +   .attach = acpi_pnp_scan_handler_attach,
> > +};
> > +
> > +bool acpi_is_pnp_device(struct acpi_device *device)
> > +{
> > +   return device->handler == &acpi_pnp_handler;
> > +}
> > +EXPORT_SYMBOL_GPL(acpi_is_pnp_device);
> > +
> > +void __init acpi_pnp_init(void)
> > +{
> > +   acpi_scan_add_handler(&acpi_pnp_handler);
> > +}
> > diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> 
> 


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