linux/Documentation/driver-api/firmware/lookup-order.rst
Luis R. Rodriguez 113ccc3837 firmware: revamp firmware documentation
Understanding this code is getting out of control without any
notes. Give the firmware_class driver a much needed documentation love,
and while at it convert it to the new sphinx documentation format.

v2: typos and small fixes

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-11 09:42:59 +01:00

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=====================
Firmware lookup order
=====================
Different functionality is available to enable firmware to be found.
Below is chronological order of how firmware will be looked for once
a driver issues a firmware API call.
* The ''Built-in firmware'' is checked first, if the firmware is present we
return it immediately
* The ''Firmware cache'' is looked at next. If the firmware is found we
return it immediately
* The ''Direct filesystem lookup'' is performed next, if found we
return it immediately
* If no firmware has been found and the fallback mechanism was enabled
the sysfs interface is created. After this either a kobject uevent
is issued or the custom firmware loading is relied upon for firmware
loading up to the timeout value.