Graphics, sound and multimedia • C779 Setup does not work (PI 4B)

Hello,

i have tried a lot on setting up the Geekworm C779 with my Raspberry PI 4B. have done it in line with the manual here https://wiki.geekworm.com/C779-Software with the following adjustment:
- Since the /boot/config.txt has moved to /boot/firmware/config.txt I have made the changes there.

I am running on the latest Raspberry PI OS lite 32 bit and also have tried it with Raspberry PI OS Lite 64 bit.

"name -a" yields:
Linux MyPI 6.12.25+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.25-1+rpt1 (2025-04-30) aarch64 GNU/Linux

the content of /etc/os-relase:
PRETTY_NAME="Raspbian GNU/Linux 12 (bookworm)"
NAME="Raspbian GNU/Linux"
VERSION_ID="12"
VERSION="12 (bookworm)"
VERSION_CODENAME=bookworm
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

So I followed the manual and did the following on a plane new installation of Raspberry PI OS lite:

1. sudo apt-get update ; sudo apt-get upgrade

2. sudo nano /boot/firmare/config.txt => added dtoverlay=tc358743 add the end of the file

content of /boot/firmware/config.txt:
------------------------------------
# For more options and information see
# http://rptl.io/configtxt
# Some settings may impact device functionality. See link above for details

# Uncomment some or all of these to enable the optional hardware interfaces
dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

# Additional overlays and parameters are documented
# /boot/firmware/overlays/README

# Automatically load overlays for detected cameras
camera_auto_detect=1

# Automatically load overlays for detected DSI displays
display_auto_detect=1

# Automatically load initramfs files, if found
auto_initramfs=1

# Enable DRM VC4 V3D driver
dtoverlay=vc4-kms-v3d
max_framebuffers=2

# Don't have the firmware create an initial video= setting in cmdline.txt.
# Use the kernel's default instead.
disable_fw_kms_setup=1

# Disable compensation for displays with overscan
disable_overscan=1

# Run as fast as firmware / board allows
arm_boost=1

[cm4]
# Enable host mode on the 2711 built-in XHCI USB controller.
# This line should be removed if the legacy DWC2 controller is required
# (e.g. for USB device mode) or if USB support is not required.
otg_mode=1

[cm5]
dtoverlay=dwc2,dr_mode=host

[all]
dtoverlay=tc358743
------------------------------------

3. sudo nano /boot/firmware/cmdline.txt => added cma=96M at the beginning

4. The device can be found as /dev/video0 after reboot
5. Created the edid.txt as shown on the website (https://wiki.geekworm.com/C779-Software)
6. v4l2-ctl --set-edid=file=edid.txt --fix-edid-checksums --verbose
7. Now the problem:
v4l2-ctl --query-dv-timings
This leads to VIDIOC_QUERY_DV_TIMINGS: failed: No locks available
Furthermore I do not see log messages of the device in "dmesg -w" when I unplug or plug it

When I connect my MAC to the C779, my MAC even recognizes the C779 and start the extension of my displays.
The final problem is that I always get "Stable sync signal:no" according to the following command: v4l2-ctl --log-status

Status Log:

[ 124.767957] unicam fe801000.csi: ================= START STATUS =================
[ 124.772059] tc358743 10-000f: -----Chip status-----
[ 124.773657] tc358743 10-000f: Chip ID: 0x00
[ 124.775172] tc358743 10-000f: Chip revision: 0x00
[ 124.775185] tc358743 10-000f: Reset: IR: 1, CEC: 1, CSI TX: 0, HDMI: 0
[ 124.775197] tc358743 10-000f: Sleep mode: off
[ 124.775205] tc358743 10-000f: Cable detected (+5V power): yes
[ 124.776483] tc358743 10-000f: DDC lines enabled: yes
[ 124.777754] tc358743 10-000f: Hotplug enabled: yes
[ 124.779094] tc358743 10-000f: CEC enabled: no
[ 124.779103] tc358743 10-000f: -----Signal status-----
[ 124.779109] tc358743 10-000f: TMDS signal detected: yes
[ 124.779115] tc358743 10-000f: Stable sync signal: no
[ 124.779121] tc358743 10-000f: PHY PLL locked: yes
[ 124.779127] tc358743 10-000f: PHY DE detected: yes
[ 124.781394] tc358743 10-000f: No video detected
[ 124.781402] tc358743 10-000f: Configured format: 640x480p59.94 (800x525)
[ 124.781416] tc358743 10-000f: horizontal: fp = 16, -sync = 96, bp = 48
[ 124.781425] tc358743 10-000f: vertical: fp = 10, -sync = 2, bp = 33
[ 124.781433] tc358743 10-000f: pixelclock: 25175000
[ 124.781441] tc358743 10-000f: flags (0x80): HAS_CEA861_VIC
[ 124.781451] tc358743 10-000f: standards (0x3): CEA DMT
[ 124.781459] tc358743 10-000f: CEA-861 VIC: 1
[ 124.781466] tc358743 10-000f: -----CSI-TX status-----
[ 124.781473] tc358743 10-000f: Lanes needed: 1
[ 124.781479] tc358743 10-000f: Lanes in use: 1
[ 124.782813] tc358743 10-000f: Waiting for particular sync signal: no
[ 124.784155] tc358743 10-000f: Transmit mode: no
[ 124.785497] tc358743 10-000f: Receive mode: no
[ 124.786832] tc358743 10-000f: Stopped: no
[ 124.786840] tc358743 10-000f: Color space: RGB 888 24-bit
[ 124.787979] tc358743 10-000f: -----DVI-D status-----
[ 124.787988] tc358743 10-000f: HDCP encrypted content: no
[ 124.787995] tc358743 10-000f: Input color space: RGB full range
[ 124.789130] unicam fe801000.csi: -----Receiver status-----
[ 124.789138] unicam fe801000.csi: V4L2 width/height: 640x480
[ 124.789146] unicam fe801000.csi: Mediabus format: 0000100a
[ 124.789154] unicam fe801000.csi: V4L2 format: 33424752
[ 124.789161] unicam fe801000.csi: Unpacking/packing: 0 / 0
[ 124.789168] unicam fe801000.csi: ----Live data----
[ 124.789174] unicam fe801000.csi: Programmed stride: 0
[ 124.789180] unicam fe801000.csi: Detected resolution: 0x0
[ 124.789187] unicam fe801000.csi: Write pointer: 00000000
[ 124.789194] unicam fe801000.csi: ================== END STATUS ==================

if you have any ideas I would be very thankful.

With best regards.

Statistics: Posted by hendrik8903 — Thu Aug 28, 2025 6:55 pm

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