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| author | Luis R. Rodriguez <mcgrof@kernel.org> | 2016-12-16 14:10:36 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-01-11 11:42:59 +0300 |
| commit | 113ccc38378b6f0b24c0993040c6044e35163a51 (patch) | |
| tree | 2a1fbd9a1ad5144dc316834ccf52505a84191cb3 /Documentation/driver-api/firmware/lookup-order.rst | |
| parent | 880444e214cfd293a2e8cc4bd3505f7ffa6ce33a (diff) | |
| download | linux-113ccc38378b6f0b24c0993040c6044e35163a51.tar.xz | |
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>
Diffstat (limited to 'Documentation/driver-api/firmware/lookup-order.rst')
| -rw-r--r-- | Documentation/driver-api/firmware/lookup-order.rst | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/driver-api/firmware/lookup-order.rst b/Documentation/driver-api/firmware/lookup-order.rst new file mode 100644 index 000000000000..88c81739683c --- /dev/null +++ b/Documentation/driver-api/firmware/lookup-order.rst @@ -0,0 +1,18 @@ +===================== +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. |