[PATCH] README.md: recommend to use INSTALL_MOD_DIR

[Luis Chamberlain]

By default depmod will only look at the updates directory for modules,
and so if one wants to replace production modules with alternatives
one can just use INSTALL_MOD_DIR=updates at modules_install time.

This will ensure that the correctly mocked modules are used, whether
that is for cxl or libnvdimm.

Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
 README.md | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index e5c4940..fd285af 100644
--- a/README.md
+++ b/README.md
@@ -74,16 +74,17 @@ loaded.  To build and install nfit_test.ko:
    CONFIG_ENCRYPTED_KEYS=y
    ```
 
-1. Build and install the unit test enabled libnvdimm modules in the
-   following order.  The unit test modules need to be in place prior to
-   the `depmod` that runs during the final `modules_install`  
+1. Build and install the unit test enabled libnvdimm modules
 
    ```
-   make M=tools/testing/nvdimm
-   sudo make M=tools/testing/nvdimm modules_install
    sudo make modules_install
+   make M=tools/testing/nvdimm
+   sudo make M=tools/testing/nvdimm modules_install INSTALL_MOD_DIR=updates
    ```
 
+To uninstall and use the production nvdimm modules just rm -rf the updates
+directory from the respective kernel /lib/modules/ directory and run depmod -a.
+
 1. Now run `meson test -C build` in the ndctl source directory, or `ndctl test`,
    if ndctl was built with `-Dtest=enabled` as a configuration option to meson.
 
-- 
2.35.1