Hello,
my Comet Pro GL-RM10 detects the HDMI connection from my PC, but always displays “No HDMI signal detected.” The source PC successfully detects the RM10 EDID and reports the HDMI connector as connected. The USB/control connection also works.
Setup
- Device: GL.iNet Comet Pro GL-RM10
- RM10 firmware: V1.9.1 release1
- LT6911C driver: 00.01.04
- LT6911C firmware: 49.25.3.3.1
- GPU: NVIDIA GeForce RTX 4090
- NVIDIA driver: 595.71.05
- OS: Nobara Linux 43
- KDE Plasma/KWin: 6.6.4
- Session: Wayland
- Connection: RTX 4090 HDMI output → RM10 HDMI IN
- Original HDMI cable supplied with the RM10
Only three GPU outputs were active, so the RTX 4090 four-display limit was not reached.
Problem
The RM10 appears to measure standard HDMI modes incorrectly. It adds one or two pixels/lines to the active resolution and then rejects the result because the dimensions are not divisible by four.
Example after a complete RM10 power cycle:
lt6911c 1-002b: driver version: 00.01.04
lt6911c 1-002b: Firmware Version: 49.25.3.3.1
lt6911c 1-002b: Resolution: 1920x1081@45 fps (htotal=2200, vtotal=1125) audio: 0 realaudio: 0
lt6911c 1-002b: lt6911c_rcv_supported_res: width and height must be divisible by 4
m00_f_lt6911c 1-002b: lt6911c_get_timing: rcv err res, return no signal!
lt6911c 1-002b: 0xD211 is ff
kvmd.apps.kvmd.api.streamer ERROR --- Stream is offline, no signal or so
The reported total timing of 2200x1125 matches normal 1080p60 timing, but the active height is incorrectly detected as 1081. The snapshot endpoint also returns HTTP 503 while this happens.
Tested modes
1280x720@60 →1282x721 at about 45 fps, rejected
1920x1080@60 → 1920/1922x1081 at about 45–49 fps, rejected
2560x1440@60 → 2562x1441 at about 44–51 fps, rejected
1024x768@60 →1024/1026x769 at about 57–60 fps, rejected
Troubleshooting already performed
- Checked the connection and HDMI IN direction
- Used the original RM10 HDMI cable
- Tested the RM10 as a cloned and independent display
- Tested 720p, 1080p, 1440p and 1024x768
- Tested the built-in GLKVM, ASUS 1080p and AOC 1024x768 EDIDs
- Forced SDR, RGB Limited and 8 bits per color
- Disabled and re-enabled the HDMI output to force a new handshake
- Soft-rebooted the RM10
- Completely disconnected and power-cycled the RM10
- Booted the RM10 while the PC HDMI output was disabled, then enabled a clean 1080p60 signal afterward
- Confirmed that the PC sees the RM10 EDID and HDMI audio/ELD information correctly
The result is always the same, this appears closely related to Bug #1 in the existing forum report:
[[BUG] Video Link negotiation Issue with GL-RM10 V1.8.2]
In that report, the LT6911C misreads a 2560x1440 input as 2562x1440 and subsequently rejects it because the dimensions are not divisible by four.
GL.iNet later stated that firmware V1.9.1 contained related optimizations. However, my RM10 is already running V1.9.1 release1, and the issue remains reproducible even after a complete power cycle. In my case it also affects several resolutions and frequently includes an additional vertical line, for example:
- 2560x1440 → 2562x1441
- 1920x1080 → 1920/1922x1081
- 1280x720 → 1282x721
- 1024x768 → 1024/1026x769
Unlike the temporary self-recovery described in the earlier report, my RM10 remains stuck in the no-signal state.
I have the original RM10 diagnostic exports for all tests available. Because they contain local network identifiers, I can provide them privately to a GL.iNet staff member upon request.