Dual Head Monitor forces memclk high state for HD6850
Follow up unresolved 6 years old bug of #273 (closed)
using kernel parameter radeon.dpm=0 and entering low power state with echo low > /sys/class/drm/card0/device/power_profile
memory clock doesn't lowered to 300Mhz as it need if two monitor attached...
echo low > /sys/class/drm/card0/device/power_profile
with single monitor attached:
[root@Ryzen device]# cat /sys/kernel/debug/dri/0/radeon_pm_info
default engine clock: 775000 kHz
current engine clock: 99990 kHz
default memory clock: 1000000 kHz
current memory clock: 300000 kHz
voltage: 950 mV
PCIE lanes: 16
echo low > /sys/class/drm/card0/device/power_profile
with dual monitor attached:
[root@Ryzen device]# cat /sys/kernel/debug/dri/0/radeon_pm_info
default engine clock: 775000 kHz
current engine clock: 99990 kHz
default memory clock: 1000000 kHz
current memory clock: 1000000 kHz
voltage: 950 mV
PCIE lanes: 16
If I switch echo low > /sys/class/drm/card0/device/power_profile
while single monitor attached, than attaching second monitor does NOT change the power states memory clock. So I continue to use 300 Mhz memclk instead of 1000 Mhz.