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 <[e-mail]>
Cc: [e-mail]

drivers/gpu/drm/radeon/kv_dpm.c

···
 	pi->caps_sclk_ds = true;
 	pi->enable_auto_thermal_throttling = true;
 	pi->disable_nb_ps3_in_battery = false;
-	pi->bapm_enable = true;
+	if (radeon_bapm == 0)
+		pi->bapm_enable = false;
+	else
+		pi->bapm_enable = true;
 	pi->voltage_drop_t = 0;
 	pi->caps_sclk_throttle_low_notification = false;
 	pi->caps_fps = false; /* true? */

drivers/gpu/drm/radeon/radeon.h

···
 extern int radeon_vm_block_size;
 extern int radeon_deep_color;
 extern int radeon_use_pflipirq;
+extern int radeon_bapm;
 
 /*
  * Copy from radeon_drv.h so we don't have to include both and have conflicting

drivers/gpu/drm/radeon/radeon_drv.c

···
 int radeon_vm_block_size = -1;
 int radeon_deep_color = 0;
 int radeon_use_pflipirq = 2;
+int radeon_bapm = -1;
 
 MODULE_PARM_DESC(no_wb, "Disable AGP writeback for scratch registers");
 module_param_named(no_wb, radeon_no_wb, int, 0444);
···
 
 MODULE_PARM_DESC(use_pflipirq, "Pflip irqs for pageflip completion (0 = disable, 1 = as fallback, 2 = exclusive (default))");
 module_param_named(use_pflipirq, radeon_use_pflipirq, int, 0444);
+
+MODULE_PARM_DESC(bapm, "BAPM support (1 = enable, 0 = disable, -1 = auto)");
+module_param_named(bapm, radeon_bapm, int, 0444);
 
 static struct pci_device_id pciidlist[] = {
 	radeon_PCI_IDS

drivers/gpu/drm/radeon/trinity_dpm.c

···
 	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;