Acer 7735z, Intel graphics, brightness control issue.

firewalker · 2010-12-11 15:10:20

Hello. I have friends Acer 7735z Laptop and trying Arch. Everything works except brightness control.

What I have tried:

ls -l /proc/acpi/video/GFX0

dr-xr-xr-x 2 root root 0 Dec 11 16:55 DD01
dr-xr-xr-x 2 root root 0 Dec 11 16:55 DD02
dr-xr-xr-x 2 root root 0 Dec 11 16:55 DD03
dr-xr-xr-x 2 root root 0 Dec 11 16:55 DD04
dr-xr-xr-x 2 root root 0 Dec 11 16:55 DD05
-rw-r--r-- 1 root root 0 Dec 11 16:55 DOS
-r--r--r-- 1 root root 0 Dec 11 16:55 info
-rw-r--r-- 1 root root 0 Dec 11 16:55 POST
-r--r--r-- 1 root root 0 Dec 11 16:55 POST_info
-r--r--r-- 1 root root 0 Dec 11 16:55 ROM

cat ./*/brightness

<not supported>
<not supported>
<not supported>
<not supported>
<not supported>

cat /sys/module/acer_wmi/parameters/brightness

-1

ls -l /sys/class/backlight/acer-wmi

-r--r--r-- 1 root root 4096 Dec 11 16:59 actual_brightness
-rw-r--r-- 1 root root 4096 Dec 11 16:59 bl_power
-rw-r--r-- 1 root root 4096 Dec 11 16:59 brightness
lrwxrwxrwx 1 root root    0 Dec 11 16:59 device -> ../../../acer-wmi
-r--r--r-- 1 root root 4096 Dec 11 16:48 max_brightness
drwxr-xr-x 2 root root    0 Dec 11 16:59 power
lrwxrwxrwx 1 root root    0 Dec 11 16:47 subsystem -> ../../../../../class/backlight
-rw-r--r-- 1 root root 4096 Dec 11 16:47 uevent

I can change the value of brightness with echo [0..9] > brightness but nothing changes.

I have tried the acpi_backlight=vendor and acpi_backlight=video (also acpi_backlight=acer_acpi) on my kernel configuration and still nothing. Disabling acpi makes it work, but the prise is to high. I tried i915.modeset=0 but modeset is mandatory for Intel gpus. I also tried the noapic option but nothing.

Is there any other suggestion?

lspci

00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09)
00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03)
00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03)
00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 2 (rev 03)
00:1c.4 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 5 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03)
00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03)
00:1d.3 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93)
00:1f.0 ISA bridge: Intel Corporation ICH9M LPC Interface Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation ICH9M/M-E SATA AHCI Controller (rev 03)
00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 03)
02:00.0 Ethernet controller: Broadcom Corporation NetLink BCM5784M Gigabit Ethernet PCIe (rev 10)
03:00.0 Network controller: Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-Express) (rev 01)

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09) (prog-if 00 [VGA controller])
        Subsystem: Acer Incorporated [ALI] Device 0261
        Flags: bus master, fast devsel, latency 0, IRQ 41
        Memory at f4000000 (64-bit, non-prefetchable) [size=4M]
        Memory at d0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at 1800 [size=8]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
        Capabilities: [d0] Power Management version 3
        Kernel driver in use: i915
        Kernel modules: i915

lagagnon · 2010-12-11 15:13:30

Did you try using "xbacklight" ?

firewalker · 2010-12-11 15:23:10

I actually can change the brightness with setpci -s 00:02.0 F4.B=[0..100]. But I don;t know if something like that is safe, or the right way to do it. Is it?

xbacklight returns No outputs have backlight property.

lagagnon · 2010-12-12 16:49:33

If nothing else works then setpci is OK. It really is just a hardware command. Obviously you want to make sure you send the right bits to the right device (or you might have to reboot your machine) but as you seem to have found what works then go for it.

histoplasmosis · 2011-02-18 01:00:59

Try adding both acpi_osi=Linux acpi_backlight=legacy to you kernel line. That should enable brightness control again. This is a bug i've seen since kernel .36 and up on these laptops. There are about 6 acer models effected all in the 7736 7735 line etc..

Last edited by histoplasmosis (2011-02-18 01:01:22)

firewalker · 2011-02-18 11:03:23

Will try some time today. Thanks you.

Arch Linux

#1 2010-12-11 15:10:20

Acer 7735z, Intel graphics, brightness control issue.

#2 2010-12-11 15:13:30

Re: Acer 7735z, Intel graphics, brightness control issue.

#3 2010-12-11 15:23:10

Re: Acer 7735z, Intel graphics, brightness control issue.

#4 2010-12-12 16:49:33

Re: Acer 7735z, Intel graphics, brightness control issue.

#5 2011-02-18 01:00:59

Re: Acer 7735z, Intel graphics, brightness control issue.

#6 2011-02-18 11:03:23

Re: Acer 7735z, Intel graphics, brightness control issue.

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