Force IT8790E and IT8792E into configuration mode

IT8790E and IT8792E need to be in configuration mode to avoid LPC bus errors.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/it87.c b/it87.c
index 43578fd5213c032d1ff00dccfbc82d8c5f90ceef..2421acf31b3dfd6008983830bebd5609b0e19b94 100644 (file)
--- a/it87.c
+++ b/it87.c
@@ -2833,6 +2833,7 @@ static int __init it87_find(int sioaddr, unsigned short *address,
                break;
        case IT8790E_DEVID:
                sio_data->type = it8790;
+               doexit = false;         /* See IT8792E comment above */
                break;
        case IT8603E_DEVID:
        case IT8623E_DEVID:
@@ -3821,9 +3822,28 @@ exit_device_put:
 }
 
 struct it87_dmi_data {
+       bool sio2_force_config; /* force sio2 into configuration mode   */
        u8 skip_pwm;            /* pwm channels to skip for this board  */
 };
 
+/*
+ * On various Gigabyte AM4 boards (AB350, AX370), the second Super-IO chip
+ * (IT8792E) needs to be in configuration mode before accessing the first
+ * due to a bug in IT8792E which otherwise results in LPC bus access errors.
+ * This needs to be done before accessing the first Super-IO chip since
+ * the second chip may have been accessed prior to loading this driver.
+ *
+ * The problem is also reported to affect IT8795E, which is used on X299 boards
+ * and has the same chip ID as IT9792E (0x8733). It also appears to affect
+ * systems with IT8790E, which is used on some Z97X-Gaming boards as well as
+ * Z87X-OC.
+ * DMI entries for those systems will be added as they become available and
+ * as the problem is confirmed to affect those boards.
+ */
+static struct it87_dmi_data gigabyte_sio2_force = {
+       .sio2_force_config = true,
+};
+
 /*
  * On the Shuttle SN68PT, FAN_CTL2 is apparently not
  * connected to a fan, but to something else. One user
@@ -3837,6 +3857,27 @@ static struct it87_dmi_data nvidia_fn68pt = {
 };
 
 static const struct dmi_system_id it87_dmi_table[] __initconst = {
+       {
+               .matches = {
+                       DMI_MATCH(DMI_SYS_VENDOR, "Gigabyte Technology Co., Ltd."),
+                       DMI_MATCH(DMI_BOARD_NAME, "AB350"),
+               },
+               .driver_data = &gigabyte_sio2_force,
+       },
+       {
+               .matches = {
+                       DMI_MATCH(DMI_SYS_VENDOR, "Gigabyte Technology Co., Ltd."),
+                       DMI_MATCH(DMI_BOARD_NAME, "AX370"),
+               },
+               .driver_data = &gigabyte_sio2_force,
+       },
+       {
+               .matches = {
+                       DMI_MATCH(DMI_SYS_VENDOR, "Gigabyte Technology Co., Ltd."),
+                       DMI_MATCH(DMI_BOARD_NAME, "Z97X-Gaming G1"),
+               },
+               .driver_data = &gigabyte_sio2_force,
+       },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "nVIDIA"),
@@ -3864,6 +3905,9 @@ static int __init sm_it87_init(void)
        if (err)
                return err;
 
+       if (dmi_data && dmi_data->sio2_force_config)
+               __superio_enter(REG_4E);
+
        for (i = 0; i < ARRAY_SIZE(sioaddr); i++) {
                memset(&sio_data, 0, sizeof(struct it87_sio_data));
                isa_address = 0;