<html><head></head><body>Hi,<br>
yes you are right, this does not control the Backlight itself. (If you set it to 0.0) you will see that the display ist still switched on.<br>
<br>
Greetings Christian<br><br><div class="gmail_quote">Am 10. März 2016 17:35:09 MEZ, schrieb Nicolas Huillard <nicolas@huillard.net>:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail">Le jeudi 10 mars 2016 à 13:26 +0100, Gee a écrit :<br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> On 03/10/2016 01:11 PM, Paul Mansfield wrote:<br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> On 10 March 2016 at 06:53, <christian@boltares.de> wrote:<br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;"> Hi,<br /><br /> as a temporary solution to the backlight problem you can use<br /><br /> xrandr --output UNKNOWN1 --brightness 0.5<br /></blockquote> <br /> that's interesting, it suggests that the driver knows how to control<br /> the backlight, we just need to find a way of linking the control with<br /> the user space tools.<br /> <br /></blockquote> <br /> As a cautionary note, I believe that xrandr doesn't actually control<br /> screen brightness on a hardware level. I jsut tested this on my current<br /> machine, where I adjust brightness with xbacklight. Even if I reduce<br /> brightness, xrandr still claims that brightness is at 1.0. I think I<br /> also saw some forum posts to this effect.<br /> <br /> So, if you're just concerned with the screen being too bright the xrandr<br /> workaround is useful, but I suspect it's not going to improve battery<br /> life (I'd be interested to hear if that can be disproved of course, but<br /> atm that's probably hard to test directly on our Click Mini as we don't<br /> have battery indication).<br /></blockquote><br />What I read from the kernel logs at boot time, is that brightness<br />control doesn't work because the PWM driving the LEDs is not available<br />(some kind of BIOS misconfiguration or wrong use, to be fixed at kernel<br />level).<br /><br />xrandr just tweaks the pixel outputs, ie. grey instead of white :<br />--brightness brightness<br /> Multiply the gamma values on the crtc currently attached to the<br /> output to specified floating value. Useful for overly bright or<br /> overly dim outputs. However, this is a software only<br /> modification, if your hardware has support to actually change<br /> the brightness, you will probably prefer to use xbacklight.<br /><br />xbacklight will hopefully use the actual LED hardware, and will probably<br />fail to adjust it, thanks to the PWM initialisation error.<br /><br />HTH<br /></pre></blockquote></div><br>
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