1 files changed, 106 insertions, 10 deletions

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index cf0f89364d44..bdabd3fd844c 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -6559,6 +6559,17 @@ static struct ibm_struct brightness_driver_data = {
  * bits 3-0 (volume).  Other bits in NVRAM may have other functions,
  * such as bit 7 which is used to detect repeated presses of MUTE,
  * and we leave them unchanged.
+ *
+ * On newer Lenovo ThinkPads, the EC can automatically change the volume
+ * in response to user input.  Unfortunately, this rarely works well.
+ * The laptop changes the state of its internal MUTE gate and, on some
+ * models, sends KEY_MUTE, causing any user code that responds to the
+ * mute button to get confused.  The hardware MUTE gate is also
+ * unnecessary, since user code can handle the mute button without
+ * kernel or EC help.
+ *
+ * To avoid confusing userspace, we simply disable all EC-based mute
+ * and volume controls when possible.
  */
 
 #ifdef CONFIG_THINKPAD_ACPI_ALSA_SUPPORT
@@ -6613,11 +6624,21 @@ enum tpacpi_volume_capabilities {
 	TPACPI_VOL_CAP_MAX
 };
 
+enum tpacpi_mute_btn_mode {
+	TP_EC_MUTE_BTN_LATCH  = 0,	/* Mute mutes; up/down unmutes */
+	/* We don't know what mode 1 is. */
+	TP_EC_MUTE_BTN_NONE   = 2,	/* Mute and up/down are just keys */
+	TP_EC_MUTE_BTN_TOGGLE = 3,	/* Mute toggles; up/down unmutes */
+};
+
 static enum tpacpi_volume_access_mode volume_mode =
 	TPACPI_VOL_MODE_MAX;
 
 static enum tpacpi_volume_capabilities volume_capabilities;
 static bool volume_control_allowed;
+static bool software_mute_requested = true;
+static bool software_mute_active;
+static int software_mute_orig_mode;
 
 /*
  * Used to syncronize writers to TP_EC_AUDIO and
@@ -6635,6 +6656,8 @@ static void tpacpi_volume_checkpoint_nvram(void)
 		return;
 	if (!volume_control_allowed)
 		return;
+	if (software_mute_active)
+		return;
 
 	vdbg_printk(TPACPI_DBG_MIXER,
 		"trying to checkpoint mixer state to NVRAM...\n");
@@ -6696,6 +6719,12 @@ static int volume_set_status_ec(const u8 status)
 
 	dbg_printk(TPACPI_DBG_MIXER, "set EC mixer to 0x%02x\n", status);
 
+	/*
+	 * On X200s, and possibly on others, it can take a while for
+	 * reads to become correct.
+	 */
+	msleep(1);
+
 	return 0;
 }
 
@@ -6778,6 +6807,57 @@ unlock:
 	return rc;
 }
 
+static int volume_set_software_mute(bool startup)
+{
+	int result;
+
+	if (!tpacpi_is_lenovo())
+		return -ENODEV;
+
+	if (startup) {
+		if (!acpi_evalf(ec_handle, &software_mute_orig_mode,
+				"HAUM", "qd"))
+			return -EIO;
+
+		dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_MIXER,
+			    "Initial HAUM setting was %d\n",
+			    software_mute_orig_mode);
+	}
+
+	if (!acpi_evalf(ec_handle, &result, "SAUM", "qdd",
+			(int)TP_EC_MUTE_BTN_NONE))
+		return -EIO;
+
+	if (result != TP_EC_MUTE_BTN_NONE)
+		pr_warn("Unexpected SAUM result %d\n",
+			result);
+
+	/*
+	 * In software mute mode, the standard codec controls take
+	 * precendence, so we unmute the ThinkPad HW switch at
+	 * startup.  Just on case there are SAUM-capable ThinkPads
+	 * with level controls, set max HW volume as well.
+	 */
+	if (tp_features.mixer_no_level_control)
+		result = volume_set_mute(false);
+	else
+		result = volume_set_status(TP_EC_VOLUME_MAX);
+
+	if (result != 0)
+		pr_warn("Failed to unmute the HW mute switch\n");
+
+	return 0;
+}
+
+static void volume_exit_software_mute(void)
+{
+	int r;
+
+	if (!acpi_evalf(ec_handle, &r, "SAUM", "qdd", software_mute_orig_mode)
+	    || r != software_mute_orig_mode)
+		pr_warn("Failed to restore mute mode\n");
+}
+
 static int volume_alsa_set_volume(const u8 vol)
 {
 	dbg_printk(TPACPI_DBG_MIXER,
@@ -6885,7 +6965,12 @@ static void volume_suspend(void)
 
 static void volume_resume(void)
 {
-	volume_alsa_notify_change();
+	if (software_mute_active) {
+		if (volume_set_software_mute(false) < 0)
+			pr_warn("Failed to restore software mute\n");
+	} else {
+		volume_alsa_notify_change();
+	}
 }
 
 static void volume_shutdown(void)
@@ -6901,6 +6986,9 @@ static void volume_exit(void)
 	}
 
 	tpacpi_volume_checkpoint_nvram();
+
+	if (software_mute_active)
+		volume_exit_software_mute();
 }
 
 static int __init volume_create_alsa_mixer(void)
@@ -7085,16 +7173,20 @@ static int __init volume_init(struct ibm_init_struct *iibm)
 			"mute is supported, volume control is %s\n",
 			str_supported(!tp_features.mixer_no_level_control));
 
-	rc = volume_create_alsa_mixer();
-	if (rc) {
-		pr_err("Could not create the ALSA mixer interface\n");
-		return rc;
-	}
+	if (software_mute_requested && volume_set_software_mute(true) == 0) {
+		software_mute_active = true;
+	} else {
+		rc = volume_create_alsa_mixer();
+		if (rc) {
+			pr_err("Could not create the ALSA mixer interface\n");
+			return rc;
+		}
 
-	pr_info("Console audio control enabled, mode: %s\n",
-		(volume_control_allowed) ?
-			"override (read/write)" :
-			"monitor (read only)");
+		pr_info("Console audio control enabled, mode: %s\n",
+			(volume_control_allowed) ?
+				"override (read/write)" :
+				"monitor (read only)");
+	}
 
 	vdbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_MIXER,
 		"registering volume hotkeys as change notification\n");
@@ -9091,6 +9183,10 @@ MODULE_PARM_DESC(volume_control,
 		 "Enables software override for the console audio "
 		 "control when true");
 
+module_param_named(software_mute, software_mute_requested, bool, 0444);
+MODULE_PARM_DESC(software_mute,
+		 "Request full software mute control");
+
 /* ALSA module API parameters */
 module_param_named(index, alsa_index, int, 0444);
 MODULE_PARM_DESC(index, "ALSA index for the ACPI EC Mixer");