drm/radeon: add bapm module parameter

Add a module paramter to enable bapm on APUs.  It's disabled
by default on certain APUs due to stability issues.  This
option makes it easier to test and to enable it on systems that
are stable.

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=81021

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/trinity_dpm.c b/drivers/gpu/drm/radeon/trinity_dpm.c
index 32e50be..57f7800 100644
--- a/drivers/gpu/drm/radeon/trinity_dpm.c
+++ b/drivers/gpu/drm/radeon/trinity_dpm.c
@@ -1874,16 +1874,22 @@
 	for (i = 0; i < SUMO_MAX_HARDWARE_POWERLEVELS; i++)
 		pi->at[i] = TRINITY_AT_DFLT;
 
-	/* There are stability issues reported on with
-	 * bapm enabled when switching between AC and battery
-	 * power.  At the same time, some MSI boards hang
-	 * if it's not enabled and dpm is enabled.  Just enable
-	 * it for MSI boards right now.
-	 */
-	if (rdev->pdev->subsystem_vendor == 0x1462)
-		pi->enable_bapm = true;
-	else
+	if (radeon_bapm == -1) {
+		/* There are stability issues reported on with
+		 * bapm enabled when switching between AC and battery
+		 * power.  At the same time, some MSI boards hang
+		 * if it's not enabled and dpm is enabled.  Just enable
+		 * it for MSI boards right now.
+		 */
+		if (rdev->pdev->subsystem_vendor == 0x1462)
+			pi->enable_bapm = true;
+		else
+			pi->enable_bapm = false;
+	} else if (radeon_bapm == 0) {
 		pi->enable_bapm = false;
+	} else {
+		pi->enable_bapm = true;
+	}
 	pi->enable_nbps_policy = true;
 	pi->enable_sclk_ds = true;
 	pi->enable_gfx_power_gating = true;