diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index a44d4b3e5beb..80310b48bfb6 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -91,6 +91,7 @@ struct pcc_chan_reg {
  * @cmd_update: PCC register bundle for the command complete update register
  * @error: PCC register bundle for the error status register
  * @plat_irq: platform interrupt
+ * @type: PCC subspace type
  */
 struct pcc_chan_info {
 	struct pcc_mbox_chan chan;
@@ -100,12 +101,15 @@ struct pcc_chan_info {
 	struct pcc_chan_reg cmd_update;
 	struct pcc_chan_reg error;
 	int plat_irq;
+	u8 type;
 };
 
 #define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan)
 static struct pcc_chan_info *chan_info;
 static int pcc_chan_count;
 
+static int pcc_send_data(struct mbox_chan *chan, void *data);
+
 /*
  * PCC can be used with perf critical drivers such as CPPC
  * So it makes sense to locally cache the virtual address and
@@ -221,6 +225,34 @@ static int pcc_map_interrupt(u32 interrupt, u32 flags)
 	return acpi_register_gsi(NULL, interrupt, trigger, polarity);
 }
 
+static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
+{
+	u64 val;
+	int ret;
+
+	ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
+	if (ret)
+		return false;
+
+	if (!pchan->cmd_complete.gas)
+		return true;
+
+	/*
+	 * Judge if the channel respond the interrupt based on the value of
+	 * command complete.
+	 */
+	val &= pchan->cmd_complete.status_mask;
+	/*
+	 * If this is PCC slave subspace channel, and the command complete
+	 * bit 0 indicates that Platform is sending a notification and OSPM
+	 * needs to respond this interrupt to process this command.
+	 */
+	if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
+		return !val;
+
+	return !!val;
+}
+
 /**
  * pcc_mbox_irq - PCC mailbox interrupt handler
  * @irq:	interrupt number
@@ -236,17 +268,9 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
 	int ret;
 
 	pchan = chan->con_priv;
-
-	ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
-	if (ret)
+	if (!pcc_mbox_cmd_complete_check(pchan))
 		return IRQ_NONE;
 
-	if (val) { /* Ensure GAS exists and value is non-zero */
-		val &= pchan->cmd_complete.status_mask;
-		if (!val)
-			return IRQ_NONE;
-	}
-
 	ret = pcc_chan_reg_read(&pchan->error, &val);
 	if (ret)
 		return IRQ_NONE;
@@ -262,6 +286,13 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
 
 	mbox_chan_received_data(chan, NULL);
 
+	/*
+	 * The PCC slave subspace channel needs to set the command complete bit
+	 * and ring doorbell after processing message.
+	 */
+	if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
+		pcc_send_data(chan, NULL);
+
 	return IRQ_HANDLED;
 }
 
@@ -698,6 +729,7 @@ static int pcc_mbox_probe(struct platform_device *pdev)
 
 		pcc_parse_subspace_shmem(pchan, pcct_entry);
 
+		pchan->type = pcct_entry->type;
 		pcct_entry = (struct acpi_subtable_header *)
 			((unsigned long) pcct_entry + pcct_entry->length);
 	}