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by kolsi
Tue Nov 19, 2019 8:43 pm
Forum: Beginners
Topic: Getting Started with FFT
Replies: 3
Views: 217

Re: Getting Started with FFT

I'm tryint to experiment with GPU_FFT and just trying to modify example hello_fft. I made this simple changes to fill the buffer with values 1, 2, 3, 4, ..., 256 (N = 256, log2_N = 8, jobs = 1): gpu_fft_prepare(mb, log2_N, GPU_FFT_FWD, jobs, &fft); base = fft->in + j*fft->step; for (i=0; i<N; i++) {...
by kolsi
Tue Nov 12, 2019 11:27 am
Forum: General discussion
Topic: HOWTO, Min Clock On Pi 3B?
Replies: 14
Views: 1775

Re: HOWTO, Min Clock On Pi 3B?

Although this topic is 3 years old, I have the same question. For our solution, we need to have stable clock and 900 MHz is very acceptable, 600 MHz is too low. So we currently use this settings: arm_freq=900 force_turbo=1 However, in some rare situations, we would like to utilize whole power and in...
by kolsi
Tue Nov 12, 2019 7:46 am
Forum: Advanced users
Topic: 16-bit depth framebuffer only
Replies: 0
Views: 72

16-bit depth framebuffer only

Hello, I have a problem when using custom compiled kernel (4.19.81-v7+) frame buffer has only 16-bit depth. Setting framebuffer_depth=32 makes no difference. Also X server displays only 16-bit colors. The same thing happens when using the latest beta kernel (sudo rpi-update), but does not happen whe...
by kolsi
Fri Sep 27, 2019 7:32 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Flowing SPI frequency with core_freq
Replies: 1
Views: 708

Re: Flowing SPI frequency with core_freq

I have a question probably similar to this topic. Raspberry Pi 3B+ can run on two CPU speeds - 600 MHz and 1400 MHz. We have Lepton camera connected via SPI bus. When CPU speed is 1400 MHz and SPI speed is set to 20 MHz then everything works correctly, but when CPU speed falls down to 600 MHz the SP...
by kolsi
Fri Sep 27, 2019 4:55 pm
Forum: Raspbian
Topic: Kweb Suite (Minimal Kiosk Browser, omxplayerGUI)
Replies: 1545
Views: 675464

Re: Kweb Suite (Minimal Kiosk Browser, omxplayerGUI)

Thank you for the information. We've redesigned our website not to use "flex" and now it renders properly in kweb. It is the only browser that seems to be usable on old Raspberry Pi B. Chromium creates many processes, eats all RAM and takes 100% CPU all the time. Even simple C++ wxWidgets app based ...
by kolsi
Wed Sep 25, 2019 8:33 am
Forum: Raspbian
Topic: Kweb Suite (Minimal Kiosk Browser, omxplayerGUI)
Replies: 1545
Views: 675464

Re: Kweb Suite (Minimal Kiosk Browser, omxplayerGUI)

We're trying to migrate from chromium to kweb on Raspberry Pi B. But we notice that it does not support CSS property "display: flex". Is there some workaround for it?

We need this <div class="row">:

Code: Select all

.row {
  display: flex;
  flex-wrap: wrap;
}
by kolsi
Thu Sep 12, 2019 12:37 pm
Forum: Troubleshooting
Topic: /etc/systemd deleted on apt upgrade
Replies: 3
Views: 150

Re: /etc/systemd deleted on apt upgrade

I added additional info to the first post.
by kolsi
Thu Sep 12, 2019 12:10 pm
Forum: Troubleshooting
Topic: /etc/systemd deleted on apt upgrade
Replies: 3
Views: 150

/etc/systemd deleted on apt upgrade

Hello, maybe someone could help me. Yesterday I did "sudo apt update + sudo apt-upgrade", after reboot everything stopped working. Raspberry boots but services do not start, so no network etc. After some investigation I discovered that the original content of /etc/systemd is completely missing. Ther...
by kolsi
Thu Jun 20, 2019 9:07 am
Forum: Graphics, sound and multimedia
Topic: Webserver for watching network cameras
Replies: 0
Views: 412

Webserver for watching network cameras

Hello, we have 8 network cameras that stream over RTSP protocol (H264 and MPEG4). We use RPi2B which displays image from 4 cameras on TV using omxplayer. This works excellent, CPU+resources usage is really low. However, we would like to install some kind of easy webserver too on this RPi where we co...
by kolsi
Wed Jun 12, 2019 11:03 am
Forum: General discussion
Topic: Unclear on throttling
Replies: 10
Views: 818

Re: Unclear on throttling

Is it normal that "vcgencmd measure_clock arm" still returns 1200000000 or 1400000000 on Rpi3B+ regardless the set scaling_governor? When scaling_governor is set to "performance", scaling_cur_freq returns correctly 1.4 GHz. When scaling_governor is set to "powersave", scaling_cur_freq returns correc...
by kolsi
Wed May 29, 2019 11:04 am
Forum: Advanced users
Topic: Disable USB ports
Replies: 14
Views: 18420

Re: Disable USB ports

Yes, you are right. I did some experiments and it is possible to disable individual ports '1-1.x.y' but they are still powered in the disabled state (e.g. USB flash disk is off, its LED is off but I can still charge my phone in the disabled port). Only completely disabling '1-1' turns the power off.
by kolsi
Fri May 17, 2019 8:59 am
Forum: Advanced users
Topic: Disable USB ports
Replies: 14
Views: 18420

Re: Disable USB ports

You CANNOT control the power to individual USB ports on a RPi. The power pins are commoned by PCB tracking. No software can change that. A bit older topic, but just a question. Is the statement above true for RPi3B+ ? ~$ lsusb -t /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M |__ ...
by kolsi
Wed Apr 03, 2019 7:57 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Tweaking SPI transfers
Replies: 0
Views: 197

Tweaking SPI transfers

Hello, we have Raspberry Pi 3B and thermal camera Lepton 3.5 in Pure Engineering board connected via SPI. Full updated Raspbian Stretch Lite. When we want to stream the image from the camera, it starts correctly but after a while we start receiving invalid frames, possibly due to loss of synchroniza...
by kolsi
Thu Mar 28, 2019 7:54 pm
Forum: Advanced users
Topic: Speed up Raspbian boot
Replies: 7
Views: 995

Re: Speed up Raspbian boot

I disabled dphys-swapfile.service too. RPi has 1 GB RAM and purpose of our system is to execute only one application at startup (that requires only a few MBs of RAM), so swapping is not needed. I'm also thinking that some kind of service dependencies reorganization would be better than completely di...
by kolsi
Mon Mar 25, 2019 8:52 am
Forum: Advanced users
Topic: Speed up Raspbian boot
Replies: 7
Views: 995

Re: Speed up Raspbian boot

You are right, it is not hardcoded in kernel but editable in cmdline.txt. But I guess that any change would require device restarting, am I right? I just tried "sudo systemctl disable..." for ssh, dhcpcd, networking and systemd-timesyncd service, the result is: Startup finished in 1.034s (kernel) + ...
by kolsi
Sat Mar 23, 2019 11:43 am
Forum: Advanced users
Topic: Speed up Raspbian boot
Replies: 7
Views: 995

Re: Speed up Raspbian boot

I don't know about systemd. But if you could also try using the kernel's built-in IP configuration. See the "ip=" parameter here . Not restricted to NFS. Might be a way for the host to be on the network without slowing down boot too much. I don't see IP built in kernel config as the solution. The I...
by kolsi
Thu Mar 21, 2019 11:34 am
Forum: Advanced users
Topic: Speed up Raspbian boot
Replies: 7
Views: 995

Speed up Raspbian boot

I have manage to optimize RPi3B+ with Raspbian Stretch Lite to boot into our GTK+2 GUI application in 4.5 seconds (3.228 secs + Xorg). [email protected]:~$ systemd-analyze Startup finished in 1.050s (kernel) + 2.178s (userspace) = 3.228s This boot time is excellent for our purpose. Now majority of the boot tim...
by kolsi
Thu Jan 24, 2019 10:58 am
Forum: Raspbian
Topic: Custom splash screen during Xserver startup
Replies: 1
Views: 240

Re: Custom splash screen during Xserver startup

Maybe, if nobody knows the answer, could someone know how to decrease the X server load time. It could at least reduce the time when the "darkness" appears and splash screen would not be needed. If I look into Xorg.0.log, I found this: ... [7.666] (EE) AIGLX: reverting to software rendering [9.291] ...
by kolsi
Wed Jan 23, 2019 10:50 am
Forum: Raspbian
Topic: Custom splash screen during Xserver startup
Replies: 1
Views: 240

Custom splash screen during Xserver startup

Hello, I'm asking a question about setting my own custom splash screen during Raspbian startup. We have Raspberry Pi3 where our GTK application should load immediately upon startup and some logo should be displayed during the boot process. System: Raspbian 9.6 (stretch) I replaced image in /usr/shar...

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