+static int hp_blike_system(u32 subsystem_id);
+
+static void set_hp_led_gpio(struct hda_codec *codec)
+{
+ struct sigmatel_spec *spec = codec->spec;
+ unsigned int gpio;
+
+ if (spec->gpio_led)
+ return;
+
+ gpio = snd_hda_param_read(codec, codec->afg, AC_PAR_GPIO_CAP);
+ gpio &= AC_GPIO_IO_COUNT;
+ if (gpio > 3)
+ spec->gpio_led = 0x08; /* GPIO 3 */
+ else
+ spec->gpio_led = 0x01; /* GPIO 0 */
+}
+
+/*
+ * This method searches for the mute LED GPIO configuration
+ * provided as OEM string in SMBIOS. The format of that string
+ * is HP_Mute_LED_P_G or HP_Mute_LED_P
+ * where P can be 0 or 1 and defines mute LED GPIO control state (low/high)
+ * that corresponds to the NOT muted state of the master volume
+ * and G is the index of the GPIO to use as the mute LED control (0..9)
+ * If _G portion is missing it is assigned based on the codec ID
+ *
+ * So, HP B-series like systems may have HP_Mute_LED_0 (current models)
+ * or HP_Mute_LED_0_3 (future models) OEM SMBIOS strings
+ *
+ *
+ * The dv-series laptops don't seem to have the HP_Mute_LED* strings in
+ * SMBIOS - at least the ones I have seen do not have them - which include
+ * my own system (HP Pavilion dv6-1110ax) and my cousin's
+ * HP Pavilion dv9500t CTO.
+ * Need more information on whether it is true across the entire series.
+ * -- kunal
+ */
+static int find_mute_led_gpio(struct hda_codec *codec, int default_polarity)
+{
+ struct sigmatel_spec *spec = codec->spec;
+ const struct dmi_device *dev = NULL;
+
+ if ((codec->subsystem_id >> 16) == PCI_VENDOR_ID_HP) {
+ while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING,
+ NULL, dev))) {
+ if (sscanf(dev->name, "HP_Mute_LED_%d_%d",
+ &spec->gpio_led_polarity,
+ &spec->gpio_led) == 2) {
+ spec->gpio_led = 1 << spec->gpio_led;
+ return 1;
+ }
+ if (sscanf(dev->name, "HP_Mute_LED_%d",
+ &spec->gpio_led_polarity) == 1) {
+ set_hp_led_gpio(codec);
+ return 1;
+ }
+ }
+
+ /*
+ * Fallback case - if we don't find the DMI strings,
+ * we statically set the GPIO - if not a B-series system.
+ */
+ if (!hp_blike_system(codec->subsystem_id)) {
+ set_hp_led_gpio(codec);
+ spec->gpio_led_polarity = default_polarity;
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static int hp_blike_system(u32 subsystem_id)
+{
+ switch (subsystem_id) {
+ case 0x103c1520:
+ case 0x103c1521:
+ case 0x103c1523:
+ case 0x103c1524:
+ case 0x103c1525:
+ case 0x103c1722:
+ case 0x103c1723:
+ case 0x103c1724:
+ case 0x103c1725:
+ case 0x103c1726:
+ case 0x103c1727:
+ case 0x103c1728:
+ case 0x103c1729:
+ case 0x103c172a:
+ case 0x103c172b:
+ case 0x103c307e:
+ case 0x103c307f:
+ case 0x103c3080:
+ case 0x103c3081:
+ case 0x103c7007:
+ case 0x103c7008:
+ return 1;
+ }
+ return 0;
+}
+