Kontron KTT20-pITX - Manual (Page 40)

KTD-S0045-D Page 36 Linux® BSP
KTT20/pITX Software Guide
67 DACR Sidetone None
68 DACL Sidetone None
69 Right Capture Mux Right
70 Left Capture Mux Left
71 ADC Input ADC
72 Right Input Mode Mux Single-Ended
73 Right Input Inverting Mux IN1R
74 Right Input Mux IN1R
75 Left Input Mode Mux Single-Ended
76 Left Input Inverting Mux IN1L
77 Left Input Mux IN1L
78 Int Spk Switch on
9.4 PCI Express ® Interface
Some mini PCI Express ® cards cause a malfunction (e.g. card not detected or interrupt assignment not pos-
sible). One way to bypass this issue is to decrease the clock frequency. For this purpose you can expand the
U-Boot environment with a new kernel argument
low_pcie_freq .
Observe the following procedure:
S
Interrupt the kernel boot process in U-Boot.
S
Type editenv bootargs.base and press Enter.
S
Add a space and then the new argument. Press Enter.
S
Type saveenv and press Enter.
Example:
Kontron KTT20 # editenv bootargs.base
edit: mem=1024M@0M console=ttyS0,115200n8 console=tty0 lp0_vec=0x2000@0x1C406000 low_pcie_freq
Kontron KTT20 # saveenv
Saving Environment to SPI Flash...
SF: Detected SST25VF032B with page size 4096, total 4 MiB
Erasing SPI flash...Writing to SPI flash...done
Kontron KTT20 #
In the same way you can remove this new argument with the backspace key.
9.5 CPU Frequency Management
Linux ® uses as default the frequency setting Ondemand which is not optimal for some applications (e.g.
video decoding). The Linux ® applet indicator-cpufreq provides four different CPU frequency modes:
Conservative, Ondemand, Powersave and Performance.
Download this tool with the following terminal commands:
(sudo) add-apt-repository ppa:artfwo/ppa
(sudo) apt-get update
(sudo) apt-get install indicator-cpufreq
After download you should reboot the operating system.