diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
index e802f9a95f08..a0e2111eb783 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c
@@ -55,7 +55,7 @@
 
 #undef __SMU_DUMMY_MAP
 #define __SMU_DUMMY_MAP(type)	#type
-static const char* __smu_message_names[] = {
+static const char * const __smu_message_names[] = {
 	SMU_MESSAGE_TYPES
 };
 
@@ -76,55 +76,258 @@ static void smu_cmn_read_arg(struct smu_context *smu,
 	*arg = RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_82);
 }
 
-int smu_cmn_wait_for_response(struct smu_context *smu)
+/* Redefine the SMU error codes here.
+ *
+ * Note that these definitions are redundant and should be removed
+ * when the SMU has exported a unified header file containing these
+ * macros, which header file we can just include and use the SMU's
+ * macros. At the moment, these error codes are defined by the SMU
+ * per-ASIC unfortunately, yet we're a one driver for all ASICs.
+ */
+#define SMU_RESP_NONE           0
+#define SMU_RESP_OK             1
+#define SMU_RESP_CMD_FAIL       0xFF
+#define SMU_RESP_CMD_UNKNOWN    0xFE
+#define SMU_RESP_CMD_BAD_PREREQ 0xFD
+#define SMU_RESP_BUSY_OTHER     0xFC
+#define SMU_RESP_DEBUG_END      0xFB
+
+/**
+ * __smu_cmn_poll_stat -- poll for a status from the SMU
+ * smu: a pointer to SMU context
+ *
+ * Returns the status of the SMU, which could be,
+ *    0, the SMU is busy with your previous command;
+ *    1, execution status: success, execution result: success;
+ * 0xFF, execution status: success, execution result: failure;
+ * 0xFE, unknown command;
+ * 0xFD, valid command, but bad (command) prerequisites;
+ * 0xFC, the command was rejected as the SMU is busy;
+ * 0xFB, "SMC_Result_DebugDataDumpEnd".
+ *
+ * The values here are not defined by macros, because I'd rather we
+ * include a single header file which defines them, which is
+ * maintained by the SMU FW team, so that we're impervious to firmware
+ * changes. At the moment those values are defined in various header
+ * files, one for each ASIC, yet here we're a single ASIC-agnostic
+ * interface. Such a change can be followed-up by a subsequent patch.
+ */
+static u32 __smu_cmn_poll_stat(struct smu_context *smu)
 {
 	struct amdgpu_device *adev = smu->adev;
-	uint32_t cur_value, i, timeout = adev->usec_timeout * 20;
+	int timeout = adev->usec_timeout * 20;
+	u32 reg;
 
-	for (i = 0; i < timeout; i++) {
-		cur_value = RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90);
-		if ((cur_value & MP1_C2PMSG_90__CONTENT_MASK) != 0)
-			return cur_value;
+	for ( ; timeout > 0; timeout--) {
+		reg = RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90);
+		if ((reg & MP1_C2PMSG_90__CONTENT_MASK) != 0)
+			break;
 
 		udelay(1);
 	}
 
-	/* timeout means wrong logic */
-	if (i == timeout)
-		return -ETIME;
-
-	return RREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90);
+	return reg;
 }
 
-int smu_cmn_send_msg_without_waiting(struct smu_context *smu,
-				     uint16_t msg, uint32_t param)
+static void __smu_cmn_reg_print_error(struct smu_context *smu,
+				      u32 reg_c2pmsg_90,
+				      int msg_index,
+				      u32 param,
+				      enum smu_message_type msg)
 {
 	struct amdgpu_device *adev = smu->adev;
-	int ret;
+	const char *message = smu_get_message_name(smu, msg);
 
-	ret = smu_cmn_wait_for_response(smu);
-	if (ret != 0x1) {
-		dev_err(adev->dev, "Msg issuing pre-check failed(0x%x) and "
-		       "SMU may be not in the right state!\n", ret);
-		if (ret != -ETIME)
-			ret = -EIO;
-		return ret;
+	switch (reg_c2pmsg_90) {
+	case SMU_RESP_NONE:
+		dev_err_ratelimited(adev->dev,
+				    "SMU: I'm not done with your previous command!");
+		break;
+	case SMU_RESP_OK:
+		/* The SMU executed the command. It completed with a
+		 * successful result.
+		 */
+		break;
+	case SMU_RESP_CMD_FAIL:
+		/* The SMU executed the command. It completed with an
+		 * unsuccessful result.
+		 */
+		break;
+	case SMU_RESP_CMD_UNKNOWN:
+		dev_err_ratelimited(adev->dev,
+				    "SMU: unknown command: index:%d param:0x%08X message:%s",
+				    msg_index, param, message);
+		break;
+	case SMU_RESP_CMD_BAD_PREREQ:
+		dev_err_ratelimited(adev->dev,
+				    "SMU: valid command, bad prerequisites: index:%d param:0x%08X message:%s",
+				    msg_index, param, message);
+		break;
+	case SMU_RESP_BUSY_OTHER:
+		dev_err_ratelimited(adev->dev,
+				    "SMU: I'm very busy for your command: index:%d param:0x%08X message:%s",
+				    msg_index, param, message);
+		break;
+	case SMU_RESP_DEBUG_END:
+		dev_err_ratelimited(adev->dev,
+				    "SMU: I'm debugging!");
+		break;
+	default:
+		dev_err_ratelimited(adev->dev,
+				    "SMU: response:0x%08X for index:%d param:0x%08X message:%s?",
+				    reg_c2pmsg_90, msg_index, param, message);
+		break;
 	}
+}
+
+static int __smu_cmn_reg2errno(struct smu_context *smu, u32 reg_c2pmsg_90)
+{
+	int res;
+
+	switch (reg_c2pmsg_90) {
+	case SMU_RESP_NONE:
+		/* The SMU is busy--still executing your command.
+		 */
+		res = -ETIME;
+		break;
+	case SMU_RESP_OK:
+		res = 0;
+		break;
+	case SMU_RESP_CMD_FAIL:
+		/* Command completed successfully, but the command
+		 * status was failure.
+		 */
+		res = -EIO;
+		break;
+	case SMU_RESP_CMD_UNKNOWN:
+		/* Unknown command--ignored by the SMU.
+		 */
+		res = -EOPNOTSUPP;
+		break;
+	case SMU_RESP_CMD_BAD_PREREQ:
+		/* Valid command--bad prerequisites.
+		 */
+		res = -EINVAL;
+		break;
+	case SMU_RESP_BUSY_OTHER:
+		/* The SMU is busy with other commands. The client
+		 * should retry in 10 us.
+		 */
+		res = -EBUSY;
+		break;
+	default:
+		/* Unknown or debug response from the SMU.
+		 */
+		res = -EREMOTEIO;
+		break;
+	}
+
+	return res;
+}
+
+static void __smu_cmn_send_msg(struct smu_context *smu,
+			       u16 msg,
+			       u32 param)
+{
+	struct amdgpu_device *adev = smu->adev;
 
 	WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90, 0);
 	WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_82, param);
 	WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_66, msg);
-
-	return 0;
 }
 
+/**
+ * smu_cmn_send_msg_without_waiting -- send the message; don't wait for status
+ * @smu: pointer to an SMU context
+ * @msg_index: message index
+ * @param: message parameter to send to the SMU
+ *
+ * Send a message to the SMU with the parameter passed. Do not wait
+ * for status/result of the message, thus the "without_waiting".
+ *
+ * Return 0 on success, -errno on error if we weren't able to _send_
+ * the message for some reason. See __smu_cmn_reg2errno() for details
+ * of the -errno.
+ */
+int smu_cmn_send_msg_without_waiting(struct smu_context *smu,
+				     uint16_t msg_index,
+				     uint32_t param)
+{
+	u32 reg;
+	int res;
+
+	if (smu->adev->no_hw_access)
+		return 0;
+
+	mutex_lock(&smu->message_lock);
+	reg = __smu_cmn_poll_stat(smu);
+	res = __smu_cmn_reg2errno(smu, reg);
+	if (reg == SMU_RESP_NONE ||
+	    reg == SMU_RESP_BUSY_OTHER ||
+	    res == -EREMOTEIO)
+		goto Out;
+	__smu_cmn_send_msg(smu, msg_index, param);
+	res = 0;
+Out:
+	mutex_unlock(&smu->message_lock);
+	return res;
+}
+
+/**
+ * smu_cmn_wait_for_response -- wait for response from the SMU
+ * @smu: pointer to an SMU context
+ *
+ * Wait for status from the SMU.
+ *
+ * Return 0 on success, -errno on error, indicating the execution
+ * status and result of the message being waited for. See
+ * __smu_cmn_reg2errno() for details of the -errno.
+ */
+int smu_cmn_wait_for_response(struct smu_context *smu)
+{
+	u32 reg;
+
+	reg = __smu_cmn_poll_stat(smu);
+	return __smu_cmn_reg2errno(smu, reg);
+}
+
+/**
+ * smu_cmn_send_smc_msg_with_param -- send a message with parameter
+ * @smu: pointer to an SMU context
+ * @msg: message to send
+ * @param: parameter to send to the SMU
+ * @read_arg: pointer to u32 to return a value from the SMU back
+ *            to the caller
+ *
+ * Send the message @msg with parameter @param to the SMU, wait for
+ * completion of the command, and return back a value from the SMU in
+ * @read_arg pointer.
+ *
+ * Return 0 on success, -errno on error, if we weren't able to send
+ * the message or if the message completed with some kind of
+ * error. See __smu_cmn_reg2errno() for details of the -errno.
+ *
+ * If we weren't able to send the message to the SMU, we also print
+ * the error to the standard log.
+ *
+ * Command completion status is printed only if the -errno is
+ * -EREMOTEIO, indicating that the SMU returned back an
+ * undefined/unknown/unspecified result. All other cases are
+ * well-defined, not printed, but instead given back to the client to
+ * decide what further to do.
+ *
+ * The return value, @read_arg is read back regardless, to give back
+ * more information to the client, which on error would most likely be
+ * @param, but we can't assume that. This also eliminates more
+ * conditionals.
+ */
 int smu_cmn_send_smc_msg_with_param(struct smu_context *smu,
 				    enum smu_message_type msg,
 				    uint32_t param,
 				    uint32_t *read_arg)
 {
-	struct amdgpu_device *adev = smu->adev;
-	int ret = 0, index = 0;
+	int res, index;
+	u32 reg;
 
 	if (smu->adev->no_hw_access)
 		return 0;
@@ -136,31 +339,24 @@ int smu_cmn_send_smc_msg_with_param(struct smu_context *smu,
 		return index == -EACCES ? 0 : index;
 
 	mutex_lock(&smu->message_lock);
-	ret = smu_cmn_send_msg_without_waiting(smu, (uint16_t)index, param);
-	if (ret)
-		goto out;
-
-	ret = smu_cmn_wait_for_response(smu);
-	if (ret != 0x1) {
-		if (ret == -ETIME) {
-			dev_err(adev->dev, "message: %15s (%d) \tparam: 0x%08x is timeout (no response)\n",
-				smu_get_message_name(smu, msg), index, param);
-		} else {
-			dev_err(adev->dev, "failed send message: %15s (%d) \tparam: 0x%08x response %#x\n",
-				smu_get_message_name(smu, msg), index, param,
-				ret);
-			ret = -EIO;
-		}
-		goto out;
+	reg = __smu_cmn_poll_stat(smu);
+	res = __smu_cmn_reg2errno(smu, reg);
+	if (reg == SMU_RESP_NONE ||
+	    reg == SMU_RESP_BUSY_OTHER ||
+	    res == -EREMOTEIO) {
+		__smu_cmn_reg_print_error(smu, reg, index, param, msg);
+		goto Out;
 	}
-
+	__smu_cmn_send_msg(smu, (uint16_t) index, param);
+	reg = __smu_cmn_poll_stat(smu);
+	res = __smu_cmn_reg2errno(smu, reg);
+	if (res == -EREMOTEIO)
+		__smu_cmn_reg_print_error(smu, reg, index, param, msg);
 	if (read_arg)
 		smu_cmn_read_arg(smu, read_arg);
-
-	ret = 0; /* 0 as driver return value */
-out:
+Out:
 	mutex_unlock(&smu->message_lock);
-	return ret;
+	return res;
 }
 
 int smu_cmn_send_smc_msg(struct smu_context *smu,
diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h
index 9add5f16ff56..16993daa2ae0 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.h
@@ -27,7 +27,8 @@
 
 #if defined(SWSMU_CODE_LAYER_L2) || defined(SWSMU_CODE_LAYER_L3) || defined(SWSMU_CODE_LAYER_L4)
 int smu_cmn_send_msg_without_waiting(struct smu_context *smu,
-				     uint16_t msg, uint32_t param);
+				     uint16_t msg_index,
+				     uint32_t param);
 int smu_cmn_send_smc_msg_with_param(struct smu_context *smu,
 				    enum smu_message_type msg,
 				    uint32_t param,