From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Thu, 3 Mar 2016 21:36:34 -0600
Subject: [PATCH 46/82] ASoC: Intel: common: filter ACPI devices with _STA return value
Git-commit: cab473850226c3e41823453b5b80eb294dae6e0c
Patch-mainline: 4.6-rc1
References: bsc#1010690

BIOS vendors typically list multiple audio codecs in the DSDT
table and enable the relevant one by changing the return value
of the _STA method.

With the current code, all devices are reported by
acpi_dev_present(), regardless of the _STA return values. This
causes errors on probe with the wrong machine driver being loaded.

This patch essentially reverts 'commit 6f08cbdaac5a
("asoc: Intel: Use acpi_dev_present()")' and adds code to
force the evaluation of the _STA method.

A better solution might be to make sure the ACPI subsystem only
reports devices with a _STA value of 0xf but apparently it's
problematic so dealing with this in the audio subsystem directly.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 sound/soc/intel/common/sst-match-acpi.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/sound/soc/intel/common/sst-match-acpi.c
+++ b/sound/soc/intel/common/sst-match-acpi.c
@@ -23,7 +23,14 @@
 static acpi_status sst_acpi_mach_match(acpi_handle handle, u32 level,
 				       void *context, void **ret)
 {
+	unsigned long long sta;
+	acpi_status status;
+
 	*(bool *)context = true;
+	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
+	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
+		*(bool *)context = false;
+
 	return AE_OK;
 }
 
@@ -37,7 +44,6 @@ struct sst_acpi_mach *sst_acpi_find_mach
 						  sst_acpi_mach_match,
 						  &found, NULL)) && found)
 			return mach;
-
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(sst_acpi_find_machine);
