At Sat, 19 Nov 2011 10:34:12 -0800, Keith Packard wrote: > > [1 <text/plain (quoted-printable)>] > On Sat, 19 Nov 2011 11:05:05 +0100, Takashi Iwai <tiwai at suse.de> wrote: > > > Maybe it'd be better to mention that actually setting bit-0 caused a > > blank screen on some machines. > > Was that caused by *just* setting bit zero? Or was it caused by setting > the duty cycle to 0xffff, in which case it would be larger than the > maximum value? > > I'll clean up the commit log message with your answer and then push this out. According to Daniels' original post: On 11/04/2011 03:36 PM, Daniel Mack wrote: > I'm facing a bug on a Samsung X20 notebook which features an i915 > chipset (output of 'lspci -v' attached). > > The effect is that setting the backlight to odd values causes the value > to be misinterpreted. Harald Hoyer (cc:) had the same thing on a Netbook > (I don't recall which model it was). > > So this will turn the backlight to full brightness: > > # cat /sys/class/backlight/intel_backlight/max_brightness > 29750 > # echo 29750 > /sys/class/backlight/intel_backlight/brightness > > However, writing 29749 will turn the display backlight off, and 29748 > appears to be the next valid lower value. So, writing bit-0 caused a problem, as it seems. Takashi
