diff --git a/sound/isa/cmi8330.c b/sound/isa/cmi8330.c
index 3d1f19321b9e..ecff521957cb 100644
--- a/sound/isa/cmi8330.c
+++ b/sound/isa/cmi8330.c
@@ -103,8 +103,8 @@ MODULE_PARM_DESC(mpuport, "MPU-401 port # for CMI8330/CMI8329 driver.");
 module_param_hw_array(mpuirq, int, irq, NULL, 0444);
 MODULE_PARM_DESC(mpuirq, "IRQ # for CMI8330/CMI8329 MPU-401 port.");
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnp_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
 #endif
 
 #define CMI8330_RMUX3D    16
diff --git a/sound/isa/cs423x/cs4236.c b/sound/isa/cs423x/cs4236.c
index e36cc147651a..238065ffa1d2 100644
--- a/sound/isa/cs423x/cs4236.c
+++ b/sound/isa/cs423x/cs4236.c
@@ -69,9 +69,9 @@ module_param_hw_array(dma2, int, dma, NULL, 0444);
 MODULE_PARM_DESC(dma2, "DMA2 # for " IDENT " driver.");
 
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnpc_registered;
-static int pnp_registered;
+static int isa_registered __ro_after_init;
+static int pnpc_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
 #endif /* CONFIG_PNP */
 
 struct snd_card_cs4236 {
diff --git a/sound/isa/es18xx.c b/sound/isa/es18xx.c
index 1da7b400a17b..df88d91e0fb2 100644
--- a/sound/isa/es18xx.c
+++ b/sound/isa/es18xx.c
@@ -1924,9 +1924,9 @@ module_param_hw_array(dma2, int, dma, NULL, 0444);
 MODULE_PARM_DESC(dma2, "DMA 2 # for ES18xx driver.");
 
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnp_registered;
-static int pnpc_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
+static int pnpc_registered __ro_after_init;
 
 static const struct pnp_device_id snd_audiodrive_pnpbiosids[] = {
 	{ .id = "ESS1869" },
diff --git a/sound/isa/gus/interwave.c b/sound/isa/gus/interwave.c
index 6c3a2977dcb3..115f900fa063 100644
--- a/sound/isa/gus/interwave.c
+++ b/sound/isa/gus/interwave.c
@@ -111,8 +111,8 @@ struct snd_interwave {
 
 
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnp_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
 
 static const struct pnp_card_device_id snd_interwave_pnpids[] = {
 #ifndef SNDRV_STB
diff --git a/sound/isa/msnd/msnd_pinnacle.c b/sound/isa/msnd/msnd_pinnacle.c
index 5b729bb02ef6..0d5f4461a7bc 100644
--- a/sound/isa/msnd/msnd_pinnacle.c
+++ b/sound/isa/msnd/msnd_pinnacle.c
@@ -1199,8 +1199,8 @@ static int snd_msnd_pnp_resume(struct pnp_card_link *pcard)
 }
 #endif
 
-static int isa_registered;
-static int pnp_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
 
 static const struct pnp_card_device_id msnd_pnpids[] = {
 	/* Pinnacle PnP */
diff --git a/sound/isa/opl3sa2.c b/sound/isa/opl3sa2.c
index 8c1767697b62..88eada933a1f 100644
--- a/sound/isa/opl3sa2.c
+++ b/sound/isa/opl3sa2.c
@@ -69,9 +69,9 @@ module_param_array(opl3sa3_ymode, int, NULL, 0444);
 MODULE_PARM_DESC(opl3sa3_ymode, "Speaker size selection for 3D Enhancement mode: Desktop/Large Notebook/Small Notebook/HiFi.");
 
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnp_registered;
-static int pnpc_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
+static int pnpc_registered __ro_after_init;
 #endif
 
 /* control ports */
diff --git a/sound/isa/sb/sb16.c b/sound/isa/sb/sb16.c
index 208d1942a015..866d7f5c58a0 100644
--- a/sound/isa/sb/sb16.c
+++ b/sound/isa/sb/sb16.c
@@ -99,8 +99,8 @@ MODULE_PARM_DESC(seq_ports, "Number of sequencer ports for WaveTable synth.");
 #endif
 
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnp_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
 #endif
 
 struct snd_card_sb16 {
diff --git a/sound/isa/sscape.c b/sound/isa/sscape.c
index 553ceb92d298..ce8a59650e38 100644
--- a/sound/isa/sscape.c
+++ b/sound/isa/sscape.c
@@ -71,8 +71,8 @@ module_param_array(joystick, bool, NULL, 0444);
 MODULE_PARM_DESC(joystick, "Enable gameport.");
 
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnp_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
 
 static const struct pnp_card_device_id sscape_pnpids[] = {
 	{ .id = "ENS3081", .devs = { { "ENS0000" } } }, /* Soundscape PnP */
diff --git a/sound/isa/wavefront/wavefront.c b/sound/isa/wavefront/wavefront.c
index f4a0c21c905e..5b1917cc19ce 100644
--- a/sound/isa/wavefront/wavefront.c
+++ b/sound/isa/wavefront/wavefront.c
@@ -71,8 +71,8 @@ module_param_array(use_cs4232_midi, bool, NULL, 0444);
 MODULE_PARM_DESC(use_cs4232_midi, "Use CS4232 MPU-401 interface (inaccessibly located inside your computer)");
 
 #ifdef CONFIG_PNP
-static int isa_registered;
-static int pnp_registered;
+static int isa_registered __ro_after_init;
+static int pnp_registered __ro_after_init;
 
 static const struct pnp_card_device_id snd_wavefront_pnpids[] = {
 	/* Tropez */