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-rw-r--r--drivers/acpi/Kconfig20
-rw-r--r--drivers/acpi/blacklist.c26
-rw-r--r--drivers/acpi/internal.h1
-rw-r--r--drivers/acpi/osl.c18
4 files changed, 65 insertions, 0 deletions
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ab2cbb51c6aa..2b652f1d4edb 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -77,6 +77,26 @@ config ACPI_PROCFS_POWER
Say N to delete power /proc/acpi/ directories that have moved to /sys/
+config ACPI_REV_OVERRIDE_POSSIBLE
+ bool "Allow supported ACPI revision to be overriden"
+ depends on X86
+ default y
+ help
+ The platform firmware on some systems expects Linux to return "5" as
+ the supported ACPI revision which makes it expose system configuration
+ information in a special way.
+
+ For example, based on what ACPI exports as the supported revision,
+ Dell XPS 13 (2015) configures its audio device to either work in HDA
+ mode or in I2S mode, where the former is supposed to be used on Linux
+ until the latter is fully supported (in the kernel as well as in user
+ space).
+
+ This option enables a DMI-based quirk for the above Dell machine (so
+ that HDA audio is exposed by the platform firmware to the kernel) and
+ makes it possible to force the kernel to return "5" as the supported
+ ACPI revision via the "acpi_rev_override" command line switch.
+
config ACPI_EC_DEBUGFS
tristate "EC read/write access through /sys/kernel/debug/ec"
default n
diff --git a/drivers/acpi/blacklist.c b/drivers/acpi/blacklist.c
index 1d1791935c31..278dc4be992a 100644
--- a/drivers/acpi/blacklist.c
+++ b/drivers/acpi/blacklist.c
@@ -162,6 +162,15 @@ static int __init dmi_disable_osi_win8(const struct dmi_system_id *d)
acpi_osi_setup("!Windows 2012");
return 0;
}
+#ifdef CONFIG_ACPI_REV_OVERRIDE_POSSIBLE
+static int __init dmi_enable_rev_override(const struct dmi_system_id *d)
+{
+ printk(KERN_NOTICE PREFIX "DMI detected: %s (force ACPI _REV to 5)\n",
+ d->ident);
+ acpi_rev_override_setup(NULL);
+ return 0;
+}
+#endif
static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
{
@@ -325,6 +334,23 @@ static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
DMI_MATCH(DMI_PRODUCT_NAME, "1015PX"),
},
},
+
+#ifdef CONFIG_ACPI_REV_OVERRIDE_POSSIBLE
+ /*
+ * DELL XPS 13 (2015) switches sound between HDA and I2S
+ * depending on the ACPI _REV callback. If userspace supports
+ * I2S sufficiently (or if you do not care about sound), you
+ * can safely disable this quirk.
+ */
+ {
+ .callback = dmi_enable_rev_override,
+ .ident = "DELL XPS 13 (2015)",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "XPS 13 9343"),
+ },
+ },
+#endif
{}
};
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index ba4a61e964be..42f304288829 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -58,6 +58,7 @@ void acpi_cmos_rtc_init(void);
#else
static inline void acpi_cmos_rtc_init(void) {}
#endif
+int acpi_rev_override_setup(char *str);
extern bool acpi_force_hot_remove;
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 39748bb3a543..37e592798cd5 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -537,6 +537,19 @@ acpi_os_get_physical_address(void *virt, acpi_physical_address * phys)
}
#endif
+#ifdef CONFIG_ACPI_REV_OVERRIDE_POSSIBLE
+static bool acpi_rev_override;
+
+int __init acpi_rev_override_setup(char *str)
+{
+ acpi_rev_override = true;
+ return 1;
+}
+__setup("acpi_rev_override", acpi_rev_override_setup);
+#else
+#define acpi_rev_override false
+#endif
+
#define ACPI_MAX_OVERRIDE_LEN 100
static char acpi_os_name[ACPI_MAX_OVERRIDE_LEN];
@@ -555,6 +568,11 @@ acpi_os_predefined_override(const struct acpi_predefined_names *init_val,
*new_val = acpi_os_name;
}
+ if (!memcmp(init_val->name, "_REV", 4) && acpi_rev_override) {
+ printk(KERN_INFO PREFIX "Overriding _REV return value to 5\n");
+ *new_val = (char *)5;
+ }
+
return AE_OK;
}