Bug 11146

Summary:	[PATCH- needs work]Sony TX series and possible other Sony laptops couldn't use the lowest brightness setting (sony-laptop)
Product:	Drivers	Reporter:	unggnu
Component:	Other	Assignee:	Alan (alan)
Status:	RESOLVED OBSOLETE
Severity:	low	CC:	alan, malattia
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.31	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	my patch which fixes the problem for the TX series DSDT.dsl dmidecode output

Description unggnu 2008-07-22 06:41:02 UTC

Distribution: Ubuntu Hardy 8.04
Hardware Environment: Sony Vaio TX2
Software Environment: i386
Problem Description:
Sony TX series and possible other Sony laptops (most likely all Sony LEDs laptop displays) couldn't use the lowest brightness setting because the sony-laptop.c allows only eight level instead of nine possible in this series.
I use a patch to make all nine level accessible but it would break brightness for other Sony laptops.
The current sony-laptop implementation has the brightness value 0 but this is actually a 1 within the deprecated sony-acpi implementation and for the TX series.

Steps to reproduce:
1. increase brightness to maximum
2. check that /sys/class/backlight/sony/brightness shows only 7 instead of 8

Comment 1 unggnu 2008-07-22 06:43:38 UTC

Created attachment 16936 [details]
my patch which fixes the problem for the TX series

Just for the records my patch which would most likely break brightness for other Sony laptops.

Comment 2 unggnu 2008-07-22 06:47:06 UTC

Created attachment 16937 [details]
DSDT.dsl

Comment 3 unggnu 2008-07-22 06:47:35 UTC

Created attachment 16938 [details]
dmidecode output

Comment 4 unggnu 2009-12-10 11:28:02 UTC

Any news about this bug. This still seems to be an issue at least with 2.6.31. Since many Sony laptops now have a LED display I think they also might have this bug.