Bug 45311 - [PATCH]After the brightness level decreasing it's not possible to increase it back higher some limited level (Samsung RV520 laptop)
[PATCH]After the brightness level decreasing it's not possible to increase it...
Status: NEW
Product: Drivers
Classification: Unclassified
Component: Platform_x86
All Linux
: P1 normal
Assigned To: drivers_platform_x86@kernel-bugs.osdl.org
:
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2012-07-30 05:06 UTC by carasin
Modified: 2016-03-07 15:13 UTC (History)
2 users (show)

See Also:
Kernel Version: >= 3.4
Tree: Mainline
Regression: Yes


Attachments
The <samsing-laptop> source (from a too old kernel version) with added RV520 support (20.37 KB, application/octet-stream)
2012-07-30 05:18 UTC, carasin
Details
<Makefile> for building the module with attached <samsung-laptop.c> (291 bytes, application/octet-stream)
2012-07-30 05:24 UTC, carasin
Details

Description carasin 2012-07-30 05:06:27 UTC
At the kernel >= 3.4 (samsung-laptop module) there has been appeared a Samsung RV520 laptop support (Product Name: RV420/RV520/RV720/E3530/S3530/E3420/E3520).

But the trouble with brightness adjustment exists:

When I try to change the brightness level, the maximum brightness limit becomes very low (~20...30%). Then, when I press <Fn + Up> (brightness up) further, a backlight is blinking for a short time, but the brightness level doesn't change. <Fn + Down> (brightness down) works well.

If I unplug the supply cable and then plug it back, the brightness level becomes maximum (100%). But after decreasing the brightness level the problem with <Fn + Up> repeats again.

> # cat /sys/devices/platform/samsung/backlight/samsung/max_brightness 
> 8
>
> # echo 8 > /sys/devices/platform/samsung/backlight/samsung/actual_brightness
> -bash: /sys/devices/platform/samsung/backlight/samsung/actual_brightness: Permission denied

But the backlight is blinking for a short time, if I execute this:

> # echo 8 > /sys/devices/platform/samsung/backlight/samsung/brightness

I've updated kernel up to 3.5.0 ― the situation is the same: after the brightness level decreasing it's not possible to increase it back higher some limited level. That's some console output (after <Fn + Down> to min and <Fn + Up> to "max"):

> $ cat /sys/devices/platform/samsung/backlight/samsung/actual_brightness 
> 2
>
> $ cat /sys/devices/platform/samsung/backlight/samsung/brightness 
> 8
>
> $ cat /sys/devices/platform/samsung/backlight/samsung/max_brightness 
> 8
Comment 1 carasin 2012-07-30 05:14:02 UTC
The workaround is a using the rebuilt <samsung-laptop.ko> module (with the attached <samsung-laptop.ko> and <Makefile>).
Comment 2 carasin 2012-07-30 05:18:55 UTC
Created attachment 76471 [details]
The <samsing-laptop> source (from a too old kernel version) with added RV520 support
Comment 3 carasin 2012-07-30 05:24:28 UTC
Created attachment 76491 [details]
<Makefile> for building the module with attached <samsung-laptop.c>

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