camera: prepare CAMX overlay runtime for NHX validation

Runner/suites/Multimedia/Camera/Camera_NHX/README_Camera_NHX.md

@@ -75,16 +75,18 @@ Snapshot JSON files are currently expected only for targets where the files are
      - `qcom,cam-tpg1031`
      - `qcom,camera`
    - `fdtdump` scan for camera-related nodes through `lib_camera.sh`
-   - Camera kernel module detection and loaded-state validation
+   - Camera kernel module detection and loaded-state validation, including `camera_x1e80100` on Glymur
    - ICP firmware presence check (`CAMERA_ICP`)
    - `dmesg` scan for camera warnings/errors
-   - CAMX package presence check
+   - CAMX package presence check through the available `opkg`, Debian, or RPM package database
+   - With `--overlay`, an unavailable package inventory is warn-only after the package set was verified successfully
    - Sensor presence check is warn-only because NHX may still work depending on target/test config
 
 4. **Runs NHX**
+   - Resolves `nhx.sh` from `PATH`, then falls back to the packaged CAMX location `/usr/libexec/camx/nhx.sh`.
    - Default mode runs `nhx.sh` with no argument, preserving the existing SoC-specific default behavior.
    - Optional mode accepts one selected JSON via `--json` and optionally `--target`.
-   - The selected JSON is staged to the location expected by `/usr/bin/nhx.sh`.
+   - The selected JSON is staged to the location expected by the selected `nhx.sh` launcher.
 
 5. **Dump validation**
    - Collects dump file list from NHX output and/or dump directory based on a marker timestamp.
@@ -116,17 +118,18 @@ installs the `camera-nhx` package set:
 camx-dkms camx-glymur libcamx-glymur1 camx-firmware-glymur camx-nhx
 ```
 
-To select a FIT DTB, pass its compatibility name with `--fit-dtb`. For CAMX,
-the compatibility name is `camx`:
+`--overlay` requires the CAMX FIT DTB and uses the compatibility name `camx`.
+The same requirement can be stated explicitly with `--fit-dtb camx`:
 
 ```sh
 ./run.sh --overlay --fit-dtb camx
 ```
 
 The test discovers the platform's `VendorDtbOverlays` EFI variable with
 `efivar -l`. The EFI variable GUID is never supplied by the user or hardcoded
-in the test. It writes the requested FIT DTB name without a trailing newline,
-verifies the value through `efivar -p`, and synchronizes storage.
+in the test. It verifies that the payload is `camx` through `efivar -p`. If it
+is not selected, the test writes `camx` without a trailing newline, reads the
+variable back, and synchronizes storage.
 
 When a new DTB selection is written, the test records `Camera_NHX SKIP` with a
 reboot-required message instead of rebooting within the LAVA test shell. Reboot
@@ -138,9 +141,11 @@ reboot
 ./run.sh --overlay --fit-dtb camx
 ```
 
-If the requested FIT DTB is already selected, the test continues directly to
-the normal NHX checks. `--overlay` without `--fit-dtb` only performs the
-optional package preparation and does not change the boot DTB.
+If the CAMX FIT DTB is already selected, the test continues with runtime DT and
+camera-module checks. A loaded board-specific camera module is used as runtime
+evidence that the current boot has activated the CAMX camera stack. If EFI is
+set to `camx` but the module is not loaded, the test records SKIP and asks the
+operator to reboot manually. The test never issues a reboot itself.
 
 ---
 
@@ -233,7 +238,7 @@ In that case, pass `--target`:
 
 ## How JSON staging works
 
-`/usr/bin/nhx.sh` does not accept an arbitrary absolute JSON path. It expects a JSON name and internally checks:
+The `nhx.sh` launcher does not accept an arbitrary absolute JSON path. It expects a JSON name and internally checks:
 
 ```sh
 /etc/camera/test/NHX/${JSON_FILE}.json
@@ -278,11 +283,11 @@ Options:
 
 ```text
 --overlay          Install the optional Camera NHX CAMX package set on Debian,
-                   Ubuntu, or CentOS.
+                   Ubuntu, or CentOS and ensure the CAMX FIT DTB is selected.
 
 --fit-dtb NAME     Select NAME as the FIT DTB compatibility name for the next
                    boot. Requires --overlay on a supported desktop distro.
-                   Use camx to select the CAMX DTB overlay.
+                   Camera_NHX accepts camx, which is the --overlay default.
 
 --json JSON_FILE   NHX JSON file to pass to nhx.sh.
                    Can be absolute, relative to Camera_NHX/, or relative
@@ -301,7 +306,7 @@ Examples:
 ```
 
 ```sh
-./run.sh --overlay --fit-dtb camx
+./run.sh --overlay
 ```
 
 ```sh
@@ -453,9 +458,10 @@ run:
 
 ### SKIP
 
-- Missing CAMX prerequisites, such as DT patterns, camera module artifact/loaded state, ICP firmware, CAMX packages, or `nhx.sh`
-- The requested FIT DTB selection was written and a reboot is required before validation
-- `VendorDtbOverlays` is unavailable when `--overlay --fit-dtb` was requested
+- Missing CAMX prerequisites, such as DT patterns, camera module artifact/loaded state, ICP firmware, CAMX packages, or an executable `nhx.sh` in `PATH` or `/usr/libexec/camx`
+- The CAMX FIT DTB selection was written and a manual reboot is required before validation
+- EFI selects `camx`, but the board-specific camera module is not loaded, so a manual reboot is required
+- `VendorDtbOverlays` is unavailable when `--overlay` was requested
 - `fdtdump` is not available or camera node evidence is inconclusive
 - Requested `--json` file is not found
 - Requested JSON filename is ambiguous and `--target` was not supplied