[PATCH AUTOSEL 4.9 47/87] ACPI / video: Refactor and fix dmi_is_desktop()

[PATCH AUTOSEL 4.9 47/87] ACPI / video: Refactor and fix dmi_is_desktop()

[Sasha Levin]

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit cecf3e3e0803462335e25d083345682518097334 ]

This commit refactors the chassis-type detection introduced by
commit 53fa1f6e8a59 ("ACPI / video: Only default only_lcd to true on
Win8-ready _desktops_") (where desktop means anything without a builtin
screen).

The DMI chassis_type is an unsigned integer, so rather then doing a
whole bunch of string-compares on it, convert it to an int and feed
the result to a switch case.

Note the switch case uses hex values, this is done because the spec
uses hex values too. This changes the check for "Main Server Chassis"
from checking for 11 decimal to 11 hexadecimal, this is a bug fix,
the original check for 11 decimal was wrong.

Fixes: 53fa1f6e8a59 ("ACPI / video: Only default only_lcd to true ...")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[ rjw: Drop redundant return statements ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/acpi_video.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index 667dc5c86fef..d79e38abd6d9 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -2069,21 +2069,28 @@ static int __init intel_opregion_present(void)
 	return opregion;
 }
 
+/* Check if the chassis-type indicates there is no builtin LCD panel */
 static bool dmi_is_desktop(void)
 {
 	const char *chassis_type;
+	unsigned long type;
 
 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
 	if (!chassis_type)
 		return false;
 
-	if (!strcmp(chassis_type, "3") || /*  3: Desktop */
-	    !strcmp(chassis_type, "4") || /*  4: Low Profile Desktop */
-	    !strcmp(chassis_type, "5") || /*  5: Pizza Box */
-	    !strcmp(chassis_type, "6") || /*  6: Mini Tower */
-	    !strcmp(chassis_type, "7") || /*  7: Tower */
-	    !strcmp(chassis_type, "11"))  /* 11: Main Server Chassis */
+	if (kstrtoul(chassis_type, 10, &type) != 0)
+		return false;
+
+	switch (type) {
+	case 0x03: /* Desktop */
+	case 0x04: /* Low Profile Desktop */
+	case 0x05: /* Pizza Box */
+	case 0x06: /* Mini Tower */
+	case 0x07: /* Tower */
+	case 0x11: /* Main Server Chassis */
 		return true;
+	}
 
 	return false;
 }
-- 
2.19.1

[PATCH AUTOSEL 4.9 87/87] ACPI / video: Extend chassis-type detection with a "Lunch Box" check

[Sasha Levin]

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit d693c008e3ca04db5916ff72e68ce661888a913b ]

Commit 53fa1f6e8a59 ("ACPI / video: Only default only_lcd to true on
Win8-ready _desktops_") introduced chassis type detection, limiting the
lcd_only check for the backlight to devices where the chassis-type
indicates their is no builtin LCD panel.

The purpose of the lcd_only check is to avoid advertising a backlight
interface on desktops, since skylake and newer machines seem to always
have a backlight interface even if there is no LCD panel. The limiting
of this check to desktops only was done to avoid breaking backlight
support on some laptops which do not have the lcd flag set.

The Fujitsu ESPRIMO Q910 which is a compact (NUC like) desktop machine
has a chassis type of 0x10 aka "Lunch Box". Without the lcd_only check
we end up falsely advertising backlight/brightness control on this
device. This commit extend the dmi_is_desktop check to return true
for type 0x10 to fix this.

Fixes: 53fa1f6e8a59 ("ACPI / video: Only default only_lcd to true ...")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/acpi_video.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index d79e38abd6d9..ea0573176894 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -2088,6 +2088,7 @@ static bool dmi_is_desktop(void)
 	case 0x05: /* Pizza Box */
 	case 0x06: /* Mini Tower */
 	case 0x07: /* Tower */
+	case 0x10: /* Lunch Box */
 	case 0x11: /* Main Server Chassis */
 		return true;
 	}
-- 
2.19.1