platform/chrome: cros_ec_lpc: do not try DMI match when ACPI device found

Older models of Chromebooks did not describe the LPC EC in their ACPI
tables; starting with Strago-based devices Google is using GOOG0004 device
to describe EC LPC.

DMI-based match is fragile and does not work reliably, especially when
using custom firmware. It is also not needed when we can locate the right
ACPI device, so let's stop bailing out when DMI does not match but the
right ACPI device is present.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Benson Leung <bleung@chromium.org>

diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 3682e1539251386c658117d1b031d5c08b7fc77f..31c8b8c49e458f5be62b9aec0dbedd436785f84c 100644 (file)
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -435,7 +435,13 @@ static int __init cros_ec_lpc_init(void)
        int ret;
        acpi_status status;
 
-       if (!dmi_check_system(cros_ec_lpc_dmi_table)) {
+       status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device,
+                                 &cros_ec_lpc_acpi_device_found, NULL);
+       if (ACPI_FAILURE(status))
+               pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME);
+
+       if (!cros_ec_lpc_acpi_device_found &&
+           !dmi_check_system(cros_ec_lpc_dmi_table)) {
                pr_err(DRV_NAME ": unsupported system.\n");
                return -ENODEV;
        }
@@ -450,11 +456,6 @@ static int __init cros_ec_lpc_init(void)
                return ret;
        }
 
-       status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device,
-                                 &cros_ec_lpc_acpi_device_found, NULL);
-       if (ACPI_FAILURE(status))
-               pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME);
-
        if (!cros_ec_lpc_acpi_device_found) {
                /* Register the device, and it'll get hooked up automatically */
                ret = platform_device_register(&cros_ec_lpc_device);