1080p Raspbian Issue

(Daniel Blair) #1

I have tried Raspbian and Ubuntu on my M3 so far, it is fantastic. I am however running into an issue where I can only display at 1080. This is fine for my TV or my large monitor, but sucks for my 7" project LCD. Anybody able to lower the resolution?

(zhiz z) #2

where did you get a m3?

(Daniel Blair) #3

Not sure how that is relevant but I received an evaluation copy. Probably have to recompile the OS images to allow for auto detection of screen size and additional resolutions.

(zhiz z) #4

Not sure if you saw that.

(Daniel Blair) #5

I didn’t think to look in the M2 forum but this actually helps with my M2 board as well.


Hi there, where did you get your M3? I’ve always wanted to get one though


Hi Dan,

Do you really have a M3? If so, could you provide us results of such a test?


Do you want to access the LCD through HDMI or LVDS? I ask because you have to adjust sysfex file in different ways and you’ll realize that some of the typical 7" resolutions (1024x600 for example) are not available through HDMI in the early boot process but might be later set through fbset.

Therefore the two questions are: HDMI vs. LVDS? Which resolution?

Anyway: Since you seem to have an M3 lying around could you please do some testing as Tido already asked?

(Daniel Blair) #9

Well, both. I have an LCD that connects via a ribbon cable I want to test. I also have a small LCD (7") that I would like to use with the board. Works great with larger displays right now haha.

(Daniel Blair) #10

Yeah I could run some tests after work today.


Ok, be prepared that you’ve to start with https://github.com/BPI-SINOVOIP/BPI-M3-bsp to do something simple as adjusting the display resolution that’s defined somewhere in so called sysfex files (I’ts unbelievable but SinoVoip still ships the M3 with an u-boot version without script.bin support). But it would be better to first get details (resolution, which display needs which connection) and then continue.

I reworked the test setup a bit. The first two lines show the available cpufreq governors and frequencies, then the 3 benchmark tools are installed and performance settings adjusted to the upper limits. Afterwards two sets of test runs, one with 8 CPU cores, the second run with just 4 (that’s important to get an idea whether throttling occurs) and the last tries to have a look what happened regarding dynamic ddr/cpufreq scaling (don’t know whether it works, but I can’t cause harm).

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

apt-get install sysbench p7zip-full mbw

echo performance >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo 2016000000 >/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
sysbench --test=cpu --cpu-max-prime=20000 run --num-threads=8
7za b
mbw -t0 256 && mbw -t1 256 && mbw -t2 256
for i in 7 6 5 4 ; do echo 0 >/sys/devices/system/cpu/cpu${i}/online ; done
sysbench --test=cpu --cpu-max-prime=20000 run --num-threads=4
7za b
mbw -t0 256 && mbw -t1 256 && mbw -t2 256

dmesg | egrep "ddrfreq|dsm|cpu_freq"

Would be great if you could paste the complete output of all commands to pastebin.com or something like that and post a link back here or in the “Performance” thread where it fits better.