YongXing LCD panel not detected on HDMI
HDMI stubbornly doesn't work for some on the team for an unknown reason. Hardware damage is not ruled out.
Symptom: the board boots, but nothing is ever shown on the screen, and it doesn't go out of standby mode.
Setup: a no-name Mini-HDMI → HDMI dongle (<4cm with the plug, competes for space with the USB plug), a HDMI → $foo cable, a display
Displays:
- a 1080x1920 (portrait), HDMI YongXing LCD panel (attached data from this one)
- DELL E207WFP 1680x1050 DVI
The cable plug/unplug events look like this:
[ 4201.094069] [drm:drm_sysfs_hotplug_event] generating hotplug event
[ 4201.118251] [drm:drm_add_display_info] HDMI-A-1: No deep color support on this HDMI sink.
[ 4201.118272] [drm:drm_add_display_info] HDMI-A-1: No deep color support on this HDMI sink.
[ 4201.118463] [drm:drm_mode_object_get] OBJ ID: 42 (2)
[ 4201.118487] [drm:drm_mode_object_get] OBJ ID: 46 (1)
[ 4201.118496] [drm:drm_mode_object_get] OBJ ID: 42 (3)
[ 4201.118500] [drm:drm_mode_object_get] OBJ ID: 42 (4)
[ 4201.118518] [drm:drm_mode_object_put] OBJ ID: 42 (5)
[ 4201.118523] [drm:drm_mode_object_put] OBJ ID: 42 (4)
[ 4201.118528] [drm:drm_mode_object_put] OBJ ID: 47 (1)
[ 4201.118534] [drm:drm_mode_object_put] OBJ ID: 46 (2)
[ 4201.118539] [drm] HDMI/DP Cable Plug In
[ 4217.822047] [drm:drm_sysfs_hotplug_event] generating hotplug event
[ 4217.822256] [drm:drm_mode_object_put] OBJ ID: 43 (1)
[ 4217.822271] [drm:drm_mode_object_put] OBJ ID: 42 (3)
[ 4217.822330] [drm] HDMI/DP Cable Plug Out
modetest output:
trying to open device 'imx-drm'...done
Connectors:
id encoder status name size (mm) modes encoders
42 0 disconnected HDMI-A-1 0x0 0 41
props:
1 EDID:
flags: immutable blob
blobs:
value:
2 DPMS:
flags: enum
enums: On=0 Standby=1 Suspend=2 Off=3
value: 0
5 link-status:
flags: enum
enums: Good=0 Bad=1
value: 0
6 non-desktop:
flags: immutable range
values: 0 1
value: 0
19 CRTC_ID:
flags: object
value: 0
fbset output:
root@pureos:~# fbset "640x480 60Hz 32bit (GTF)"
ioctl FBIOPUT_VSCREENINFO: Invalid argument
and, most confusingly:
root@pureos:~# cat /sys/class/drm/card1-HDMI-A-1/status
connected
root@pureos:~# cat /sys/class/drm/card1-HDMI-A-1/modes
root@pureos:~#
TODO: run with drm.debug=0x2f
on the kernel command line