[Intel-gfx] Very bad performance from intel chipset on Thinkpad T540p (2880x1620)

[Marc MERLIN]

On Fri, Apr 24, 2015 at 04:53:53PM +0100, Chris Wilson wrote:
> Whether of not it tears depends upon your window manager. On bare X,
> using mplayer -vo xv or -vo gl, should not tear. Under a compositing
> window manager, it depends upon how it decides to update the screen. To
> force everything to update without tearing, use
> 
> echo > /etc/X11/xorg.conf.d/90-intel.conf <<EOF
> Section "Device"
> 	Identifier "igfx"
> 	Option "TearFree"
> EndSection
> EOF

Cool, thanks for the tip and your help.

I was curious to see how my power use would be, and got about the same power
use at idle with LCD to minimum:
The battery reports a discharge rate of 12.4 W
The estimated remaining time is 7 hours, 27 minutes

Summary: 171.5 wakeups/second,  0.1 GPU ops/seconds, 0.0 VFS ops/sec and 2.0% CPU use

Power est.              Usage       Events/s    Category       Description
  3.73 W      1.9%                      Device         Display backlight
  1.16 W      4.7 ms/s      65.3        Process        [btrfs-transacti]
  741 mW      0.9 ms/s      41.9        Interrupt      [4] block(softirq)
  175 mW    156.0 µs/s       9.9        Process        [rcu_sched]


Then, if I turn my screen off (backlight 0), it actually seems to save another 7W:
The battery reports a discharge rate of 5.06 W
The estimated remaining time is 18 hours, 5 minutes

Summary: 79.4 wakeups/second,  0.2 GPU ops/seconds, 0.0 VFS ops/sec and 1.8% CPU use

Power est.              Usage       Events/s    Category       Description
  229 mW      1.4 ms/s      13.4        Process        [btrfs-transacti]
  181 mW      4.1 ms/s      10.4        Process        /usr/bin/enlightenment
  174 mW    206.2 µs/s      10.2        Interrupt      [4] block(softirq)


So the good news is that the driver sems to do fine on batteries with the
default options now.

Thanks,
Marc
-- 
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                                      .... what McDonalds is to gourmet cooking
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