linux-kernel - [PATCH v2 3/5] x86/acpi: add test for ACPI_FADT_NO

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Date:   Thu,  9 Nov 2017 14:27:37 +0100
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, Juergen Gross <jgross@...e.com>, rjw@...ysocki.net,
        len.brown@...el.com, pavel@....cz, linux-pm@...r.kernel.org
Subject: [PATCH v2 3/5] x86/acpi: add test for ACPI_FADT_NO_VGA

Add a test for ACPI_FADT_NO_VGA when scanning the FADT and set the new
flag x86_platform.legacy.no_vga accordingly.

Cc: rjw@...ysocki.net
Cc: len.brown@...el.com
Cc: pavel@....cz
Cc: linux-pm@...r.kernel.org

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 arch/x86/include/asm/x86_init.h | 1 +
 arch/x86/kernel/acpi/boot.c     | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index ad15a0fda917..260e9a85fecb 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -208,6 +208,7 @@ enum x86_legacy_i8042_state {
 struct x86_legacy_features {
 	enum x86_legacy_i8042_state i8042;
 	int rtc;
+	int no_vga;
 	int reserve_bios_regions;
 	struct x86_legacy_devices devices;
 };
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 079535e53e2a..ef9e02e614d0 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -961,6 +961,11 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table)
 		x86_platform.legacy.rtc = 0;
 	}
 
+	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_VGA) {
+		pr_debug("ACPI: probing for VGA not safe\n");
+		x86_platform.legacy.no_vga = 1;
+	}
+
 #ifdef CONFIG_X86_PM_TIMER
 	/* detect the location of the ACPI PM Timer */
 	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) {
-- 
2.12.3