[PATCH AUTOSEL 4.19 15/17] ACPI: tables: Add custom DSDT file as makefile prerequisite

[Sasha Levin]

From: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>

[ Upstream commit d1059c1b1146870c52f3dac12cb7b6cbf39ed27f ]

A custom DSDT file is mostly used during development or debugging,
and in that case it is quite likely to want to rebuild the kernel
after changing ONLY the content of the DSDT.

This patch adds the custom DSDT as a prerequisite to tables.o
to ensure a rebuild if the DSDT file is updated. Make will merge
the prerequisites from multiple rules for the same target.

Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/acpi/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 6d59aa109a91..93f667140d8a 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -8,6 +8,11 @@ ccflags-$(CONFIG_ACPI_DEBUG)	+= -DACPI_DEBUG_OUTPUT
 #
 # ACPI Boot-Time Table Parsing
 #
+ifeq ($(CONFIG_ACPI_CUSTOM_DSDT),y)
+tables.o: $(src)/../../include/$(subst $\",,$(CONFIG_ACPI_CUSTOM_DSDT_FILE)) ;
+
+endif
+
 obj-$(CONFIG_ACPI)		+= tables.o
 obj-$(CONFIG_X86)		+= blacklist.o
 
-- 
2.30.2