linux-kernel - [PATCH] acpi video: force native for Apple MacbookPro9,2

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Message-Id: <20240806-acpi-video-quirk-v1-1-369d8f7abc59@chromium.org>
Date: Tue, 06 Aug 2024 20:08:47 +0000
From: Esther Shimanovich <eshimanovich@...omium.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>, 
 Hans de Goede <hdegoede@...hat.com>
Cc: linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Esther Shimanovich <eshimanovich@...omium.org>
Subject: [PATCH] acpi video: force native for Apple MacbookPro9,2

It used to be that the MacbookPro9,2 used its native intel backlight
device until the following commit was introduced:
commit b1d36e73cc1c ("drm/i915: Don't register backlight when another
backlight should be used (v2)")
This commit forced this model to use its firmware acpi_video backlight
device instead.

That worked fine until an additional commit was added:
commit 92714006eb4d ("drm/i915/backlight: Do not bump min brightness
to max on enable")
That commit uncovered a bug in the MacbookPro 9,2's acpi_video
backlight firmware; the backlight does not come back up after resume.

Add DMI quirk to select the working native intel interface instead
so that the backlight successfully comes back up after resume.

Signed-off-by: Esther Shimanovich <eshimanovich@...omium.org>
---
 drivers/acpi/video_detect.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index c11cbe5b6eaa..2d377414f873 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -547,6 +547,14 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir9,1"),
 		},
 	},
+	{
+	 .callback = video_detect_force_native,
+	 /* Apple MacBook Pro 9,2 */
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
+		DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro9,2"),
+		},
+	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1217249 */
 	 .callback = video_detect_force_native,

---
base-commit: d9ef02e56f0fd3668b6d7cb17f9399ea53f12edd
change-id: 20240806-acpi-video-quirk-f1c9f01f07d9

Best regards,
-- 
Esther Shimanovich <eshimanovich@...omium.org>