linux-kernel - Re: 2.6.21-rc1 dims my LCD

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 26 Feb 2007 11:21:57 -0300
From:	Henrique de Moraes Holschuh <hmh@....eng.br>
To:	Jiri Kosina <jikos@...os.cz>
Cc:	Richard Purdie <rpurdie@...ys.net>, linux-kernel@...r.kernel.org
Subject: Re: 2.6.21-rc1 dims my LCD

On Mon, 26 Feb 2007, Jiri Kosina wrote:
> On Mon, 26 Feb 2007, Richard Purdie wrote:
> > > When I hit the keyboard, the brightness stays low (it's 50% of light 
> > > or so, so I could read what's on the screen, but it's uncomfortably 
> > > dim), and I have to manually raise the brightness on the LCD. Quite 
> > > annoying :) I have bisected this to your commit 
> > > 994efacdf9a087b52f71e620b58dfa526b0cf928
> > Which framebuffer driver and backlight driver are you using?
> > ("ls /sys/class/backlight/" will show which backlight it is)
> 
> It's IBM:

Please add me to the CC, then.  I noticed this thread by accident.

> $ ll /sys/class/backlight/
> drwxr-xr-x 2 root root 0 Feb 26 13:28 ibm
> 
> At the time the brightness goes low, there is '0' in 
> /sys/class/backlight/ibm/actual_brightness and 
> /sys/class/backlight/ibm/brightness

ibm-acpi does not implement display poweroff, so if a screen-saving function
on the kernel is trying to use it to shut the display off, it will either
fail to do anything, or if it ALSO sets brightness to zero, it will just dim
the display.

Richard, would you like a patch to -ENOSYS if a display power management
event reaches ibm-acpi?

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/