Messages in this thread | | | Date | Mon, 13 Jun 2011 16:50:00 -0700 | From | Greg KH <> | Subject | Re: samsung-laptop backlight control not working |
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On Wed, Jun 01, 2011 at 04:50:17PM +0200, David Herrmann wrote: > Hi Greg > > On Thu, May 19, 2011 at 8:53 PM, David Herrmann > <dh.herrmann@googlemail.com> wrote: > > On Thu, May 19, 2011 at 8:27 PM, Greg KH <gregkh@suse.de> wrote: > >> On Thu, May 19, 2011 at 08:18:16PM +0200, David Herrmann wrote: > >>> Hi > >>> > >>> I tried the new samsung-laptop driver with samsung backlight support. > >> > >> What kernel are you trying? We have some recent patches to the driver > >> to try to resolve some of these issues on your laptop. > > > > I use linus' tree. 2.6.39 > > > >>> It is detected as: > >>> [109282.931433] samsung_laptop: found laptop model 'N150P/N210P/N220P' > >>> > >>> However, backlight support is kind of weird: > >>> "echo 1 >/sys/class/backlight/samsung/brightness" > >>> does not set brightness to 1 but instead reduces brightness for 1. > >>> That is, if my current brightness setting is 8, I need to call "echo 1 > >>> >..." 7 times to get brightness value 1. > >>> > >>> "cat /sys/class/backlight...." > >>> returns 1 after the first try, though. > >>> > >>> "echo 3 >..." > >>> reduces brightness also for 1 but stops at brightness level 3 if I > >>> repeat the command. > >>> > >>> dmesg shows the following for every "echo" I call: > >>> [110690.073783] ACPI: Failed to switch the brightness > >>> > >>> Furthermore "echo 0 >..." doesn't disable backlight but instead > >>> behaves like a brightness setting below 1. > >> > >> Yeah, don't echo 0 there, that doesn't work to well. I have some > >> patches here that you can try if you want, just let me know. > > > > That would be great! I have really no idea about acpi so I can't fix > > it myself. If you could give me some git tree where I can find them, I > > could test them. > > > >>> However, I know the following works on my machine: > >>> setpci -s 00:02.0 F4.B=255 > >>> It accepts a setting between 0-255 and 255 is full brightness and 0 is > >>> backlight off. > >> > >> Don't do that, the video driver will not like you as you are changing > >> things without telling the bios that something is really happening. > >> > >> Of course you can continue to do this, it's just strongly not > >> recommended. > > > > Ouh, I didn't know that. It was recommended in some distro wiki so I > > tried it and it worked. Anyway, I thought it might give you some > > information about the N210 model. > > > >> thanks, > >> > >> greg k-h > > > > Thanks > > David > > Maybe you missed that mail, any update on this? Where could I get > those patches? ;)
Ick, sorry, they can be found at: http://git.kernel.org/?p=linux/kernel/git/gregkh/patches.git;a=tree
I need to push them to Michael soon, I've been swamped with other stuff at the moment, sorry about this.
greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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