Matthias Brugger wrote: > On 10/03/2019 19:35, Per Jessen wrote: >> Well, at least I have a vcio module that builds now, we'll see it if >> it also works. >> > > It seems that there is another thread on this mailing list, but I > wasn't able to find it. What do you want to achieve?
Hi Matthias, nothing too complex I hope, I just want to control a series of WS2812 LEDs, using the code/utilities from https://github.com/jgarff/rpi_ws281x >> The code for using the PWM to generate control signals for a line of >> WS2812Bs also uses /dev/mem to access the Raspi hardware - with the >> openSUSE kernel, this is blocked by CONFIG_STRICT_DEVMEM. I don't >> see >> any kernel argument or switch to disable that restriction. (I tried >> strict_devmem=0, didn't work). >> >> I'm rebuilding a kernel without CONFIG_STRICT_DEVMEM, but I can't >> help wondering if we shouldn't have a dedicated kernel optimized for >> use on the Raspi? Using kernel-default seems silly. >> > > In general you can provide patches against openSUSE kernel > configuaration if there is anything you think it should be > enabled/disabled. Cool, I might well make some suggestions. > STRICT_DEVMEM is a security feature so IMHO there should be a good > reason to disable it. From your email I understand that you want to > access PWM via /dev/mem. That looks wrong. The PWMs should be accessed > through the sysfs. Yes, I get the idea of /dev/mem, but I see lots of code for Raspis that is using /dev/mem ? None of what I have seen even mentions having to disable STRICT_DEVMEM. > Can you please give some more background on what you want to do and > how you try to achieve that? For controlling the WS2812, I need to transmit data at around 800kHz - with libgpiod, I was only able to generate a waveform of about 400kHz (on a gpio). I gave that up and then I stumbled on https://github.com/jgarff/rpi_ws281x which looks to be the right way to go. That code expects to use /dev/vcio for talking to the GPU mailbox as well as /dev/mem for working with the PWM. -- Per Jessen, Zürich (5.3°C) http://www.hostsuisse.com/ - dedicated server rental in Switzerland. -- To unsubscribe, e-mail: opensuse-arm+unsubscr...@opensuse.org To contact the owner, e-mail: opensuse-arm+ow...@opensuse.org
