Update comments for DEVICE_PROBE() to reflect that BUS_PROBE_DEFAULT is
now the preferred typical return value from a probe routine. Discourage the use of 0 (BUS_PROBE_SPECIFIC) as it should be used very rarely. Point the reader to the DEVICE_PROBE(9) manpage for more detailed notes on possible probe return values. Submitted by: Philip Soeberg philip-dev of soeberg net
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=222253
@ -89,28 +89,29 @@ CODE {
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* the probe before returning. The return value of DEVICE_PROBE()
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* is used to elect which driver is used - the driver which returns
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* the largest non-error value wins the election and attaches to
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* the device.
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* the device. Common non-error values are described in the
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* DEVICE_PROBE(9) manual page.
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*
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* If a driver matches the hardware, it should set the device
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* description string using device_set_desc() or
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* device_set_desc_copy(). This string is
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* used to generate an informative message when DEVICE_ATTACH()
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* is called.
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* device_set_desc_copy(). This string is used to generate an
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* informative message when DEVICE_ATTACH() is called.
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*
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* As a special case, if a driver returns zero, the driver election
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* is cut short and that driver will attach to the device
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* immediately.
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* immediately. This should rarely be used.
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*
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* For example, a probe method for a pci device driver might look
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* For example, a probe method for a PCI device driver might look
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* like this:
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*
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* @code
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* int foo_probe(device_t dev)
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* int
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* foo_probe(device_t dev)
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* {
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* if (pci_get_vendor(dev) == FOOVENDOR &&
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* pci_get_device(dev) == FOODEVICE) {
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* device_set_desc(dev, "Foo device");
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* return (0);
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* return (BUS_PROBE_DEFAULT);
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* }
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* return (ENXIO);
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* }
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@ -125,7 +126,8 @@ CODE {
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*
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* @param dev the device to probe
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*
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* @retval 0 if the driver strongly matches this device
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* @retval 0 if this is the only possible driver for this
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* device
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* @retval negative if the driver can match this device - the
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* least negative value is used to select the
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* driver
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