3 files changed, 48 insertions, 0 deletions

diff --git a/sound/pci/oxygen/oxygen.h b/sound/pci/oxygen/oxygen.h
index c500d48ea349..bd615dbffadb 100644
--- a/sound/pci/oxygen/oxygen.h
+++ b/sound/pci/oxygen/oxygen.h
@@ -18,6 +18,8 @@
 
 #define OXYGEN_IO_SIZE  0x100
 
+#define OXYGEN_EEPROM_ID        0x434d  /* "CM" */
+
 /* model-specific configuration of outputs/inputs */
 #define PLAYBACK_0_TO_I2S       0x0001
      /* PLAYBACK_0_TO_AC97_0            not implemented */
@@ -190,6 +192,7 @@ void oxygen_reset_uart(struct oxygen *chip);
 void oxygen_write_uart(struct oxygen *chip, u8 data);
 
 u16 oxygen_read_eeprom(struct oxygen *chip, unsigned int index);
+void oxygen_write_eeprom(struct oxygen *chip, unsigned int index, u16 value);
 
 static inline void oxygen_set_bits8(struct oxygen *chip,
                                     unsigned int reg, u8 value)
diff --git a/sound/pci/oxygen/oxygen_io.c b/sound/pci/oxygen/oxygen_io.c
index 05f48ef1a442..c1eb923f2ac9 100644
--- a/sound/pci/oxygen/oxygen_io.c
+++ b/sound/pci/oxygen/oxygen_io.c
@@ -269,3 +269,19 @@ u16 oxygen_read_eeprom(struct oxygen *chip, unsigned int index)
         }
         return oxygen_read16(chip, OXYGEN_EEPROM_DATA);
 }
+
+void oxygen_write_eeprom(struct oxygen *chip, unsigned int index, u16 value)
+{
+        unsigned int timeout;
+
+        oxygen_write16(chip, OXYGEN_EEPROM_DATA, value);
+        oxygen_write8(chip, OXYGEN_EEPROM_CONTROL,
+                      index | OXYGEN_EEPROM_DIR_WRITE);
+        for (timeout = 0; timeout < 10; ++timeout) {
+                msleep(1);
+                if (!(oxygen_read8(chip, OXYGEN_EEPROM_STATUS)
+                      & OXYGEN_EEPROM_BUSY))
+                        return;
+        }
+        snd_printk(KERN_ERR "EEPROM write timeout\n");
+}
diff --git a/sound/pci/oxygen/oxygen_lib.c b/sound/pci/oxygen/oxygen_lib.c
index d83c3a957323..6e1cdd2fd768 100644
--- a/sound/pci/oxygen/oxygen_lib.c
+++ b/sound/pci/oxygen/oxygen_lib.c
@@ -272,6 +272,34 @@ oxygen_search_pci_id(struct oxygen *chip, const struct pci_device_id ids[])
         return NULL;
 }
 
+static void oxygen_restore_eeprom(struct oxygen *chip,
+                                  const struct pci_device_id *id)
+{
+        if (oxygen_read_eeprom(chip, 0) != OXYGEN_EEPROM_ID) {
+                /*
+                 * This function gets called only when a known card model has
+                 * been detected, i.e., we know there is a valid subsystem
+                 * product ID at index 2 in the EEPROM.  Therefore, we have
+                 * been able to deduce the correct subsystem vendor ID, and
+                 * this is enough information to restore the original EEPROM
+                 * contents.
+                 */
+                oxygen_write_eeprom(chip, 1, id->subvendor);
+                oxygen_write_eeprom(chip, 0, OXYGEN_EEPROM_ID);
+
+                oxygen_set_bits8(chip, OXYGEN_MISC,
+                                 OXYGEN_MISC_WRITE_PCI_SUBID);
+                pci_write_config_word(chip->pci, PCI_SUBSYSTEM_VENDOR_ID,
+                                      id->subvendor);
+                pci_write_config_word(chip->pci, PCI_SUBSYSTEM_ID,
+                                      id->subdevice);
+                oxygen_clear_bits8(chip, OXYGEN_MISC,
+                                   OXYGEN_MISC_WRITE_PCI_SUBID);
+
+                snd_printk(KERN_INFO "EEPROM ID restored\n");
+        }
+}
+
 static void oxygen_init(struct oxygen *chip)
 {
         unsigned int i;
@@ -532,6 +560,7 @@ int oxygen_pci_probe(struct pci_dev *pci, int index, char *id,
                 err = -ENODEV;
                 goto err_pci_regions;
         }
+        oxygen_restore_eeprom(chip, pci_id);
         err = get_model(chip, pci_id);
         if (err < 0)
                 goto err_pci_regions;