Bug 202401

Summary:	backlight control doesn't work without acpi_backlight=vendor
Product:	ACPI	Reporter:	Abderrahim Kitouni (akitouni)
Component:	Power-Video	Assignee:	Zhang Rui (rui.zhang)
Status:	RESOLVED CODE_FIX
Severity:	normal	CC:	rui.zhang
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	4.19.12	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	quirk patch

Description Abderrahim Kitouni 2019-01-24 17:28:53 UTC

The backlight brightness control doesn't work on my Sony Vaio model VPCEH3U1E. As recommended on #nouveau I booted with acpi_backlight=vendor, and brightness control works.

Here are my system informations:
# grep '.*' /sys/class/dmi/id/*_*
/sys/class/dmi/id/bios_date:11/17/2011
/sys/class/dmi/id/bios_vendor:INSYDE
/sys/class/dmi/id/bios_version:R0190Z9
/sys/class/dmi/id/board_asset_tag:N/A
/sys/class/dmi/id/board_name:VAIO
/sys/class/dmi/id/board_serial:N/A
/sys/class/dmi/id/board_vendor:Sony Corporation
/sys/class/dmi/id/board_version:N/A
/sys/class/dmi/id/chassis_asset_tag:N/A
/sys/class/dmi/id/chassis_serial:N/A
/sys/class/dmi/id/chassis_type:10
/sys/class/dmi/id/chassis_vendor:Sony Corporation
/sys/class/dmi/id/chassis_version:N/A
/sys/class/dmi/id/product_family:VAIO
/sys/class/dmi/id/product_name:VPCEH3U1E
/sys/class/dmi/id/product_serial:27553937-5000508
/sys/class/dmi/id/product_sku:N/A
/sys/class/dmi/id/product_uuid:4d10fca0-5077-11e1-8c17-78843cfdbff4
/sys/class/dmi/id/product_version:C106WAVW
/sys/class/dmi/id/sys_vendor:Sony Corporation

# ls /sys/class/backlight/
acpi_video0
nv_backlight


Setting the brightness using acpi_video0 doesn't work, but using nv_backlight works.

Comment 1 Zhang Rui 2019-03-26 09:08:07 UTC

please attach the dmidecode so that I can propose a quirk for this platform.

Comment 2 Zhang Rui 2019-03-26 09:12:40 UTC

Created attachment 282029 [details]
quirk patch

Please confirm this patch works for you.

Comment 3 Abderrahim Kitouni 2019-03-29 08:49:02 UTC

It does work indeed. Thanks.

Comment 4 Zhang Rui 2019-04-01 01:33:14 UTC

Good to know. Patch submitted at https://patchwork.kernel.org/patch/10878917/