diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 61ab1628a057cc2c4d8b11d892d834f7e5f7773a..180102480fc06dc8b0c4d048d7f0cc75ac6c5702 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -274,6 +274,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	acpi_os_name=	[HW,ACPI] Tell ACPI BIOS the name of the OS
 			Format: To spoof as Windows 98: ="Microsoft Windows"
 
+	acpi_rev_override [ACPI] Override the _REV object to return 5 (instead
+			of 2 which is mandated by ACPI 6) as the supported ACPI
+			specification revision (when using this switch, it may
+			be necessary to carry out a cold reboot _twice_ in a
+			row to make it take effect on the platform firmware).
+
 	acpi_osi=	[HW,ACPI] Modify list of supported OS interface strings
 			acpi_osi="string1"	# add string1
 			acpi_osi="!string2"	# remove string2
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ab2cbb51c6aaccde0ec2f97af343383c6f360dff..2b652f1d4edb9279ba576cfde69262666fab5d58 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 1d1791935c318c71148a5da573effe51f9031a15..278dc4be992a49b7663223a5c6bf2215699f4c20 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 ba4a61e964be4d1d2abdb59bfab85a25aa3048c4..42f3042888293cc3cc7f3c07994e6a18eb67d90c 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 39748bb3a5430111b8cf4723462eb837137b0213..37e592798cd5212d76074fdac28ac7ac27181702 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;
 }