sound: oxygen: automatically restore overwritten EEPROM

If the EEPROM was partially overwritten (which seems to happen before the OS is
booted), restore its entire contents by deducing it from the remaining
information.

This does not have any effect on the Linux driver, which works even with
incomplete information in the EEPROM, but it makes other drivers work again.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 29 insertions, 0 deletions

diff --git a/sound/pci/oxygen/oxygen_lib.c b/sound/pci/oxygen/oxygen_lib.c
index d83c3a9..6e1cdd2 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;