On 12/13/2016 04:08 AM, Luis R. Rodriguez wrote:
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.
It does help to understand the class/API, thank you!
+Even if you have these needs there are a few reasons why you may not be +able to make use of built-in firmware: + +* Legalese - firmware is non-GPL compatible +* Some firmware may be optional +* Firmware upgrades are possible, therefore a new firmware would implicate + a complete firmware rebuild.
Could it be you meant "kernel rebuild" or "vmlinux rebuild" here?
diff --git a/Documentation/driver-api/firmware/fallback-mechanisms.rst b/Documentation/driver-api/firmware/fallback-mechanisms.rst new file mode 100644 index 000000000000..edce1d76ce29 --- /dev/null +++ b/Documentation/driver-api/firmware/fallback-mechanisms.rst @@ -0,0 +1,195 @@ +=================== +Fallback mechanisms +=================== + +A fallback mechanism is supported to allow to overcome failures to do a direct +filesystem lookup on the root filesystem or when the firmware simply cannot be +installed for practical reasons on the root filesystem. The kernel +configuration options related to supporting the firmware fallback mechanism are: + + * CONFIG_FW_LOADER_USER_HELPER: enables building the firmware fallback + mechanism. Most distributions enable this option today. If enabled but + CONFIG_FW_LOADER_USER_HELPER_FALLBACK is disabled, only the custom fallback + mechanism is available and for the request_firmware_nowait() call. + * CONFIG_FW_LOADER_USER_HELPER_FALLBACK: force enables each request to + enable the kobject uevent fallback mechanism on all firmare API calls + except request_firmware_direct(). Most distributions disable this option + today. The call request_firmware_nowait() allows for one alternative + fallback mechanism: if this kconfig option is enabled and your second + argument to request_firmware_nowait(), uevent, is set to false you are + informing the kernel that you have a custom fallback mechanism and it will + manually load the firmware. Read below for more details.
Yeah, it really asks for API simplification ;)
