[PATCH i-g-t] lib/igt_kmod: Unload/Reload the mei Modules Before Unloading/Reloading the i915/xe Driver

[Bommu Krishnaiah <krishnaiah.bommu@intel.com>]

To ensure stability and proper module management, this update introduces
changes to the handling of MEI modules when loading or unloading
the Intel i915 or Xe drivers.

Key Changes:
- Unload Order: The `mei_gsc_proxy` module is now unloaded before `mei_gsc`,
preventing potential failures during the unloading process.
- Platform-Specific Handling: On platforms where the MEI hardware is integrated
with the graphics device (e.g., DG2/BMG), the MEI modules depend on the i915/Xe driver.
Conversely, on newer platforms like CLS, where MEI hardware is separate,
this dependency does not exist. This update ensures that MEI modules are
unloaded/reloaded in the correct order based on platform-specific dependencies.

These changes address the need for a more robust handling of MEI modules across
different hardware platforms, ensuring that the i915/Xe driver can be
cleanly unloaded and reloaded without issues.

Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu@intel.com>
Cc: Kamil Konieczny <kamil.konieczny@linux.intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
---
 lib/igt_kmod.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/lib/igt_kmod.c b/lib/igt_kmod.c
index 464c0dcf4..6ee2b7afe 100644
--- a/lib/igt_kmod.c
+++ b/lib/igt_kmod.c
@@ -480,9 +480,29 @@ igt_intel_driver_load(const char *opts, const char *driver)
 {
 	int ret;
 
+	const char *mei[] = {
+		/* mei_gsc uses an i915 aux dev and the other mei mods depend on it */
+		"mei_pxp",
+		"mei_hdcp",
+		"mei_gsc_proxy",
+		"mei_gsc",
+		NULL,
+	};
+
 	if (opts)
 		igt_info("Reloading %s with %s\n\n", driver, opts);
 
+	for (const char **m = mei; *m; m++) {
+		if (igt_kmod_is_loaded(*m))
+			continue;
+
+		ret = igt_kmod_load(*m, NULL);
+		if (ret) {
+			igt_debug("Could not load %s\n", *m);
+			return ret;
+		}
+	}
+
 	ret = igt_kmod_load(driver, opts);
 	if (ret) {
 		igt_debug("Could not load %s\n", driver);
@@ -620,9 +640,14 @@ int __igt_intel_driver_unload(char **who, const char *driver)
 	const char *aux[] = {
 		/* gen5: ips uses symbol_get() so only a soft module dependency */
 		"intel_ips",
+		NULL,
+	};
+
+	const char *mei[] = {
 		/* mei_gsc uses an i915 aux dev and the other mei mods depend on it */
 		"mei_pxp",
 		"mei_hdcp",
+		"mei_gsc_proxy",
 		"mei_gsc",
 		NULL,
 	};
@@ -647,6 +672,19 @@ int __igt_intel_driver_unload(char **who, const char *driver)
 		}
 	}
 
+	for (const char **m = mei; *m; m++) {
+		if (!igt_kmod_is_loaded(*m))
+			continue;
+
+		ret = igt_kmod_unload(*m);
+		if (ret) {
+			if (who)
+				*who = strdup_realloc(*who, *m);
+
+			return ret;
+		}
+	}
+
 	if (igt_kmod_is_loaded(driver)) {
 		ret = igt_kmod_unload(driver);
 		if (ret) {
-- 
2.25.1