xref: /linux/Documentation/driver-api/firmware/fw_search_path.rst (revision 34dc1baba215b826e454b8d19e4f24adbeb7d00d)
1=====================
2Firmware search paths
3=====================
4
5The following search paths are used to look for firmware on your
6root filesystem.
7
8* fw_path_para - module parameter - default is empty so this is ignored
9* /lib/firmware/updates/UTS_RELEASE/
10* /lib/firmware/updates/
11* /lib/firmware/UTS_RELEASE/
12* /lib/firmware/
13
14The module parameter ''path'' can be passed to the firmware_class module
15to activate the first optional custom fw_path_para. The custom path can
16only be up to 256 characters long. The kernel parameter passed would be:
17
18* 'firmware_class.path=$CUSTOMIZED_PATH'
19
20There is an alternative to customize the path at run time after bootup, you
21can use the file:
22
23* /sys/module/firmware_class/parameters/path
24
25You would echo into it your custom path and firmware requested will be searched
26for there first. Be aware that newline characters will be taken into account
27and may not produce the intended effects. For instance you might want to use:
28
29echo -n /path/to/script > /sys/module/firmware_class/parameters/path
30
31to ensure that your script is being used.
32