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

PATCH In review Dmitry Torokhov 2 participants 2 messages May 22, 2018

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ChromeOS EC subdrivers Chrome hardware platform support

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Dmitry Torokhov

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2018-05-22 23:08 UTC #0 lore raw

PATCH 1/1 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 [email protected]

Signed-off-by Dmitry Torokhov <[email protected]>

---
 drivers/platform/chrome/cros_ec_lpc.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

drivers/platform/chrome/cros_ec_lpc.c +7 -6

index af89e82eecd23..a000d2fbbb0be 100644
@@ -419,7 +419,13 @@ 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;
 	}

@@ -434,11 +440,6 @@ 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);

Signature · 5 lines

2.17.0.441.gb46fe60e1d-goog


-- 
Dmitry

Benson Leung

2018-05-22 23:48 UTC #1 lore raw

Hi Dmitry,

Quoted 11 lines · Dmitry Torokhov

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 [email protected]
Signed-off-by Dmitry Torokhov <[email protected]>

Nice fix. Applied.

Thanks,
Benson

Signature · 7 lines

Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
[email protected]
Chromium OS Project
[email protected]