Rename cfg option from "enable" --> "replace"

- Allows for @qzed's kernel patch: 22ef83836c

microsoft/surface/README.md

@@ -15,7 +15,7 @@ The kernel-specific derivations are under the `kernel/` sub-directory.
 In order to simplify maintenance of the Nix code, only the most-recent kernel patch-set is expected
 to be maintained in this repo.
 
-_*NOTE:*_Some built-in Kernel config items need to be set, that aren't set by default:
+_*NOTE:*_ Some built-in Kernel config items need to be set, that aren't set by default:
 - https://github.com/linux-surface/surface-aggregator-module/wiki/Testing-and-Installing
 
 ## Firmware, Drivers and Support Tools
@@ -65,15 +65,19 @@ The most effective fix to-date is to remove the `board-2.bin` file or replace it
 `board.bin` file.
 
 The derivative in `firmware/surface-go/ath10k/` can configure this, if you set the option
-`config.hardware.microsoft-surface.firmware.surface-go-ath10k.enable` to `true`.
+`config.hardware.microsoft-surface.firmware.surface-go-ath10k.replace` to `true`.
 
-Note that this is slightly destructive, as it deletes all the `board.bin` and `board-2.bin` files
-for the `ath10k` QCA6174 device, and replaces them with KillerNetworking's version.
+_*NOTE:*_ This is destructive, as it deletes all the `board.bin` and `board-2.bin` files for the
+`ath10k` QCA6174 device, and replaces them with KillerNetworking's version.
 This is the only way (currently) to force the driver to use the new firmware.
 
 For more details, see: https://github.com/linux-surface/linux-surface/wiki/Surface-Go#wifi-firmware
 
-There was an attempt to get this firmware incorporated into the aggregate `board-2.bin`,
+_*NOTE:*_ There's some work to patch the kernel to make it easier to override which firmware file
+to use for QCA6174, which would obviate this more-destructuve approach:
+- https://github.com/linux-surface/kernel/commit/22ef83836c4aa89e9eb98de9b47ed24b6c2a1d45
+
+_*NOTE:*_ There was an attempt to get this firmware incorporated into the aggregate `board-2.bin`,
 but (as of this writing) the request appears to have been ignored:
 - https://github.com/linux-surface/linux-surface/issues/41
 

microsoft/surface/TODO.org

@@ -14,15 +14,16 @@
    - [X] Install the binaries
 ** DONE Remove `ipts` firmware derivative
    - This is only needed on the 4.19 kernel
-** DOING Investigate problem with ath10k wifi firmware on Surface Go
+** DONE Investigate problem with ath10k wifi firmware on Surface Go
 :LOGBOOK:
 - State "DOING"      from "TODO"       [2021-02-09 Tue 17:19]
+- State "DONE"       from "DOING"      [2021-03-06 Sat 15:27]
 :END:
 *** DONE README entry explaining problem(s) with nonfree firmware on Surface Go
 :LOGBOOK:
 - State "DONE"       from "TODO"       [2021-02-09 Tue 17:17]
 :END:
-*** DOING Create derivative for `ath10k` firmware on Surface Go
+*** DONE Create derivative for `ath10k` firmware on Surface Go
 :LOGBOOK:
 - State "DOING"      from "TODO"       [2021-02-09 Tue 17:18]
 :END:
@@ -31,8 +32,8 @@
     - [X] Download `board.bin` from Killer Networks?
     - [X] Install ath10k firmware fix for Surface Go
       - `board-2.bin` needs to be removed / replaced with `board.bin`
-    - [ ] Add a config option for enabling the Surface Go Firmware
-    - [ ] Replace the vendorised `board.bin` with a `fetchurl`
+    - [X] Add a config option for enabling the Surface Go Firmware
+    - [-] Replace the vendorised `board.bin` with a `fetchurl`
       - Getting HTTP 406 when using `fetchurl` or `nix-prefetch-url` that has to be diagnosed
 * Support Tools
 ** TODO Incorporate @hpfr's function(s) from this commit:

microsoft/surface/firmware/surface-go/ath10k/default.nix

@@ -5,14 +5,14 @@ in
 {
   options = {
     hardware.microsoft-surface.firmware.surface-go-ath10k = {
-      enable = lib.mkEnableOption ''Use the "board.bin" firmware for ath10k-based WiFi on Surface Go.'';
+      replace = lib.mkEnableOption ''Use the "board.bin" firmware for ath10k-based WiFi on Surface Go.'';
     };
   };
 
-  config = lib.mkIf cfg.enable {
+  config = lib.mkIf cfg.replace {
     hardware.enableAllFirmware = true;
     hardware.firmware = [
-      (pkgs.callPackage ./ath10k.nix {})
+      (pkgs.callPackage ./ath10k-replace.nix {})
     ];
 
     boot.extraModprobeConfig = lib.mkDefault ''