Debian Sid Gnome does not boot into Desktop

Hi,
As I have successfully flashed the latest Linaro’s Debian boot and root filesystem images (gnome images) into my RB5, and from the console via the debug UART :
root@linaro-gnome:~# uname -ra
Linux linaro-gnome 5.12.0-qcomlt-arm64 #175 SMP PREEMPT Fri Apr 9 10:21:56 UTC 2021 aarch64 GNU/Linux
However, there’s nothing happen on the connected HDMI display. Is there any missing step during the installation or the HDMI has not been supported yet in this release, please ?

Similar result with Linaro Debian Sid Gnome 65.

Update : It seems that the board uses Lontium LT9611 mipi-dsi to hdmi converter. However, dmesg shows :
root@linaro-gnome:~# dmesg | grep dsi
[ 0.000000] Kernel command line: root=PARTLABEL=rootfs console=tty0 console=ttyMSM0,115200n8 pci:
[ 8.405621] msm_dsi ae94000.dsi: supply gdsc not found, using dummy regulator
[ 8.441640] msm_dsi_manager_register: failed to register mipi dsi host for DSI 0
[ 8.493717] msm_dsi ae94000.dsi: supply gdsc not found, using dummy regulator
[ 8.502922] msm_dsi_manager_register: failed to register mipi dsi host for DSI 0
[ 8.558711] msm_dsi ae94000.dsi: supply gdsc not found, using dummy regulator
[ 8.588552] msm_dsi_manager_register: failed to register mipi dsi host for DSI 0
[ 8.677091] msm_dsi ae94000.dsi: supply gdsc not found, using dummy regulator
[ 8.677961] msm_dsi_manager_register: failed to register mipi dsi host for DSI 0
[ 8.731044] msm_dsi ae94000.dsi: supply gdsc not found, using dummy regulator
[ 8.751145] msm_dsi_manager_register: failed to register mipi dsi host for DSI 0
[ 9.013107] msm_dsi ae94000.dsi: supply gdsc not found, using dummy regulator
[ 9.025528] msm ae00000.mdss: bound ae94000.dsi (ops dsi_ops [msm])

Thanks in advance,
K.

Hi again,

As first investigation, the firmware of the DSI to HDMI bridge chipset is missing in Debian sysroot. I then added the file lt9611uxc_fw.bin borrowed from Yocto/OpenEmbedded into /lib/fimware and saw that the driver seemed to be successfully loaded :

root@linaro-gnome:~# dmesg | grep lt9611
[ 9.190205] lt9611uxc 5-002b: LT9611 revision: 0x17.04.93
[ 9.262095] lt9611uxc 5-002b: LT9611 version: 0x40

root@linaro-gnome:~# lsmod | grep lt9611
lontium_lt9611uxc 20480 0
drm_kms_helper 262144 2 msm,lontium_lt9611uxc
drm 585728 8 drm_kms_helper,msm,display_connector,lontium_lt9611uxc

However, there’s still nothing on the display even I set the SW4 (HDMI switch) of DIP_SW_0 to OFF or ON as described here : https://developer.qualcomm.com/qualcomm-robotics-rb5-kit/quick-start-guide/inside-the-qualcomm-robotics-rb5-kit.

Could someone help, please ?

Thanks in advance,
K.

Hi @l4es,

When the system is booted and lt8611uxc_fw.bin in place, please run as root:

echo 1 > /sys/bus/i2c/devices/5-002b/lt9611uxc_firmware

Wait for LT9611UXC firmware to be upgraded (it will take few minutes) and then reboot the board.

1 Like

Hi @Lumag,

Thanks for the useful tips. Effectively, the DSI to HDMI bridge does work but with a little “discrimination” to some HDMI displays. Possibly there’s been a question of HDMI compatibility.

BR,
K.