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by ali1234
Wed Jul 10, 2019 7:00 am
Forum: Advanced users
Topic: Anyone cross compiled QT for the Pi 4 yet.
Replies: 23
Views: 826

Re: Anyone cross compiled QT for the Pi 4 yet.

I actually build my entire sysroot and resulting image using debootstrap and chroot. No Pi is involved in any of the build process other than to actually run what I am producing as the end product. The resulting image works really well on my Pi 3b+ and also the Pi 4 with the exception of the QT ele...
by ali1234
Tue Jul 09, 2019 4:21 am
Forum: Advanced users
Topic: Anyone cross compiled QT for the Pi 4 yet.
Replies: 23
Views: 826

Re: Anyone cross compiled QT for the Pi 4 yet.

The Broadcom EGL implementation does not work on Pi 4 due to it being a different GPU. This is why Qt's brcm-eglfs platform integration does not work. Try using the mkspec for eglfs-bgm, it might work with fake KMS mode that Pi 4 uses. There is already a mkspec for it: https://code.qt.io/cgit/qt/qtb...
by ali1234
Tue Jul 09, 2019 4:07 am
Forum: Graphics, sound and multimedia
Topic: send image from PI to another PI in wifi, without network
Replies: 4
Views: 209

Re: send image from PI to another PI in wifi, without network

Video can be transmitted in raw 802.11x frames without associating or even caring if anything is listening. Here is a project which does just that: https://befinitiv.wordpress.com/wifibroadcast-analog-like-transmission-of-live-video-data/ I don't know if the broadcom drivers support it. You probably...
by ali1234
Wed Jul 03, 2019 3:30 am
Forum: Graphics, sound and multimedia
Topic: Pi Zero + Camera Board = USB webcam gadget?
Replies: 13
Views: 11811

Re: Pi Zero + Camera Board = USB webcam gadget?

I finally have this transmitting video. Here are the detailed steps to make it work: 0. Have Raspberry Pi running Buster, connected to a PC on USB cable on a data-enabled port. 1. Set "dtoverlay=dwc2" in /boot/config.txt 2. Connect rpi camera and enable it with raspi-config and then reboot. After re...
by ali1234
Tue Jul 02, 2019 7:25 pm
Forum: Graphics, sound and multimedia
Topic: Pi Zero + Camera Board = USB webcam gadget?
Replies: 13
Views: 11811

Re: Pi Zero + Camera Board = USB webcam gadget?

Yeah it is missing from bcmrpi_defconfig. Reported: https://github.com/raspberrypi/linux/issues/3042

I just tried this all on a Pi 4 with a USB webcam and it all seemed to work, but I soon as I tried to open the emulated UVC device the whole Pi froze and obviously I got no video from it.
by ali1234
Mon Jul 01, 2019 11:21 am
Forum: Graphics, sound and multimedia
Topic: Pi Zero + Camera Board = USB webcam gadget?
Replies: 13
Views: 11811

Re: Pi Zero + Camera Board = USB webcam gadget?

There are currently two things preventing this from fully working: 1. Raspbian kernel doesn't have CONFIG_USB_CONFIGFS which means the uvc-gadget.sh cannot work. You must use the legacy g_webcam instead, or build your own kernel. 2. Both the uvc-gadget C programs require that the source v4l2 device ...
by ali1234
Tue Jun 25, 2019 8:12 pm
Forum: Graphics programming
Topic: Questions about FKMS
Replies: 2
Views: 424

Re: Questions about FKMS

Thanks, I'll give it a try.

I am not using X11 at all so how slow are we talking? I'll be running a Qt/QML EGLFS application and it is noticeably slower but still acceptable with the legacy drivers on a Pi Zero.
by ali1234
Tue Jun 25, 2019 2:06 pm
Forum: Graphics programming
Topic: Questions about FKMS
Replies: 2
Views: 424

Questions about FKMS

I'll get straight to the point:

1. Which kernel configuration options are required for FKMS?

2. How do I enable FKMS without using raspi-config?

3. How do I rotate the display when X isn't running?

4. Does FKMS work on every Pi model?
by ali1234
Wed Nov 22, 2017 8:17 pm
Forum: Advanced users
Topic: MTP responder with functionfs
Replies: 4
Views: 2065

Re: MTP responder with functionfs

I have also been trying to do this.

I am not using buteo or the Ubuntu mtp responder, but instead writing my own from scratch in python. It does not need any android kernel patches etc.

It doesn't work yet but it is getting close.

https://github.com/ali1234/pymtpd
by ali1234
Tue Jun 13, 2017 2:53 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4653

Re: V1.0 has brightness control

That would work I suppose. You need to put the jumper wire in too.
by ali1234
Wed Aug 17, 2016 11:30 am
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4653

Re: V1.0 has brightness control

It kills the boost converter eventually.
by ali1234
Mon Aug 15, 2016 2:03 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4653

Re: V1.0 has brightness control

I had the hardware mod made at oshpark. Works like a charm.

http://imgur.com/a/6rdaD
by ali1234
Wed Aug 03, 2016 7:11 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4653

Re: V1.0 has brightness control

If you are brave enough it would be possible to desolder U1, R4, R5, R6, and then drop in a tiny replacement board:

Image

"X" needs a jumper wire to PP19.

edit: you also need to reflash the AVR chip to the V1.1 firmware.
by ali1234
Sun Jul 31, 2016 12:27 am
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4653

Re: V1.0 has brightness control

Okay I finally got to the bottom of this. First I reverse engineered the circuits: http://imgur.com/a/24TFn Then I found the datasheet for the backlight driver chip: http://www.onsemi.com/pub_link/Collateral/CAT4139-D.PDF Marking code indicates it is the same chip in V1.0 and V1.1. There are two dif...
by ali1234
Sat Jul 30, 2016 4:58 pm
Forum: Official Foundation Display
Topic: CE compliance for RPi + Pi Display?
Replies: 12
Views: 2853

Re: CE compliance for RPi + Pi Display?

I have not been able to determine the part number for the driver chip, but I have reverse engineered the circuit. It is a boost converter, switching at 975kHz in the V1.1 display. There is also an interesting anomaly in that the driver in the V1.0 either has a non-standard pin out, or the board has...
by ali1234
Tue Jul 26, 2016 5:54 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4653

V1.0 has brightness control

Today I reverse engineered the I2C backlight control protocol and I found something very interesting. The V1.0 display supports 256 levels of brightness control. It's just the Pi firmware which prevents you from using anything other than full on and full off. If you connect the display to your own I...
by ali1234
Thu May 12, 2016 1:31 pm
Forum: General discussion
Topic: 3G Modem Doesn't Create /dev/ttyUSB*
Replies: 3
Views: 1323

Re: 3G Modem Doesn't Create /dev/ttyUSB*

These modems often initially present themselves as a USB flash drive containing Windows drivers and software. The presence of sd/sg devices indicates that is what is happening here. The USB IDs are a red herring. As the poster above said, you need usb-modeswitch to reconfigure it in normal mode.
by ali1234
Wed Apr 13, 2016 6:07 am
Forum: General discussion
Topic: PiZero Roadmap
Replies: 159
Views: 61817

Re: PiZero Roadmap

Will the USB test points be in the same place?
by ali1234
Wed Jan 13, 2016 8:23 pm
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 44175

Re: HOWTO: Enable USB device mode on Pi Zero

Buildroot was successful for me with the following: git clone git://github.com/raspberrypi/tools git clone git://git.buildroot.net/buildroot cd buildroot git checkout 7d37754113e9c689b2a617ceb227dbd3a0135726 patch -p1 < ../tools/usbboot/buildroot.patch chmod a+x board/raspberrypi/usb_test/post_build...
by ali1234
Tue Jan 05, 2016 1:32 pm
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 44175

Re: HOWTO: Enable USB device mode on Pi Zero

On a side note, I've tried a couple of times to build the linux buildroot image as per https://github.com/raspberrypi/tools/tree/master/usbboot but failed. Have you had any joy with that? I built it before ages ago on Ubuntu and then booted it on an A+. I didn't have any problems doing so, but as s...
by ali1234
Tue Jan 05, 2016 1:54 am
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 44175

Re: HOWTO: Enable USB device mode on Pi Zero

For the people trying to use usbboot, here is a quick and dirty hack to get it working. You need to give it a FAT filesystem image with kernel.img, start.elf etc. The same stuff you would find on /boot. You can put a Linux kernel image and initrd in it. That is what the buildroot does. However, the ...

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