Comme=
nt # 17
on bug 11148=
2
from Robert
Thanks Andrew! I played around a little bit with the refresh r=
ates. Between
40-60Hz there is no difference in idle power consumption. The mem clock sta=
ys
at 875Mhz and can't be changed.
The best refresh rate with 8W idle power consumption I could get was at 39H=
z:
cvt12 5120 1440 39 -b
xrandr --output DisplayPort-2 --newmode "5120x1440_39.00_rb2" 297=
.51 5120 5128
5160 5200 1440 1453 1461 1467 +hsync -vsync
xrandr --output DisplayPort-2 --addmode DisplayPort-2 "5120x1440_39.00=
_rb2"
xrandr --output DisplayPort-2 --mode "5120x1440_39.00_rb2"
This causes the mem clock to go up to 625Mhz at first but it can be switched
back to 100Mhz with
echo "0" > /sys/class/drm/card0/device/pp_dpm_mclk
Regarding my statement when using 30Hz in the last comment:
"""
It basically works but moving windows a little bit faster or moving the mou=
se
pointer around looks "interesting".
"""
For this "flickering" that I saw and which was quite annoying I f=
ound a
workaround :-) It looked like something didn't refresh fast enough. So I
thought playing around with some frequencies would be a good idea... And the
mem clock was the obvious one to start with. So I was setting the mem clock=
to
500Mhz with
echo "1" > /sys/class/drm/card0/device/pp_dpm_mclk
Then the "flickering" went away :-) But of course that brought id=
le power
consumption to 24W. So just for fun I switched back to 100Mhz with
echo "0" > /sys/class/drm/card0/device/pp_dpm_mclk
Funny enough the "flickering" stayed away :-))) So for now after =
I start KDE
plasma I enter Konsole and execute
echo "1" > /sys/class/drm/card0/device/pp_dpm_mclk
echo "0" > /sys/class/drm/card0/device/pp_dpm_mclk
and be happy :D
One final observation: I tried out kernel 5.3-rc8. With that kernel there i=
s no
way to reduce idle power consumption. It stays at 34W regardless what you d=
o.
But with this tag
https://cgit.freedesktop.org/~agd5f/linux/tag/?h=3Ddrm-next-5.4=
-2019-08-30 (which
basically is kernel 5.3-rc3 with the Navi10 patches for kernel 5.4 - if I g=
ot
it right ;-) ) idle power consumption is as expected.=20
So my whole issue basically comes down to this: If you have a resolution of
5120x1440 and a refresh rate of > 39Hz your idle power consumption stays=
at max
and there is (at least until now) nothing you can do about it. So if I had =
used
a lower resolution or a smaller screen I wouldn't have had an issue at all =
;-)
S... happens :D
But anyways: Thanks so much for your help and also to Ilia! I'm now happy w=
ith
my setup so far. It would be very interesting if there is really some kind =
of a
cap with 5120x1444@39Hz or if this this "only" a firmware pro=
blem, a driver
problem, a config error or something completely different. Maybe we'll find=
out
in our next lives :D