Hi, I bought a new "Eye-Care" on HDMI monitor, Benq 28" HDMI / DP-1. The monitor works with the DP-1 cable attached but not with the HDMI cable attached. In settings, DP-1 shows up as red and HDMI shows as green when both cables are fitted. The problem is is that it only works through the DP-1 cable. I get a blank screen if I remove the DP-1 cable. Am I missing something or perhaps Linux Mint 19.3 doesn't support HDMI? Any assistance will be helpful, thanks.

Gael

Would help to know what the other end of the cable is plugged in to; how about hardware specs on your computer? Video? And HDMI can be touchy...have you tried leaving the other cable unplugged totally, and plugging in the HDMI cable with EVERYTHING powered down, then turning the monitor on first, then PC? HDMI detection can sometimes take a second or two. And have you set your monitor to use the HDMI input, versus the DVI?

$ inxi -Fxxzd
System:
Host: pceanadach0 Kernel: 5.5.3-050503-generic x86_64 bits: 64
compiler: gcc v: 9.2.1 Desktop: Cinnamon 4.4.8 wm: muffin dm: LightDM
Distro: Linux Mint 19.3 Tricia base: Ubuntu 18.04 bionic
Machine:
Type: Laptop Mobo: INTEL model: SKYBAY serial: <filter>
UEFI [Legacy]: American Megatrends v: 5.11 date: 08/09/2016
Battery:
Device-1: hidpp_battery_0 model: Logitech Wireless Mouse M345
serial: <filter> charge: 100% status: Discharging
Device-2: hidpp_battery_1 model: Logitech Wireless Keyboard K360
serial: <filter> charge: 100% status: Discharging
CPU:
Topology: Dual Core model: Intel Core i7-6500U bits: 64 type: MT MCP
arch: Skylake rev: 3 L2 cache: 4096 KiB
flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 20799
Speed: 499 MHz min/max: 400/3100 MHz Core speeds (MHz): 1: 500 2: 500
3: 500 4: 499
Graphics:
Device-1: Intel Skylake GT2 [HD Graphics 520] driver: i915 v: kernel
bus ID: 00:02.0 chip ID: 8086:1916
Display: x11 server: X.Org 1.19.6 driver: modesetting unloaded: fbdev,vesa
resolution: 1920x1080~60Hz
OpenGL: renderer: Mesa DRI Intel HD Graphics 520 (Skylake GT2)
v: 4.5 Mesa 19.2.8 compat-v: 3.0 direct render: Yes
Audio:
Device-1: Intel Sunrise Point-LP HD Audio driver: snd_hda_intel v: kernel
bus ID: 00:1f.3 chip ID: 8086:9d70
Device-2: Logitech HD Webcam C510 type: USB driver: snd-usb-audio,uvcvideo
bus ID: 1-2:2 chip ID: 046d:081d
Sound Server: ALSA v: k5.5.3-050503-generic
Network:
Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
driver: r8169 v: kernel port: e000 bus ID: 01:00.0 chip ID: 10ec:8168
IF: enp1s0 state: up speed: 100 Mbps duplex: full mac: <filter>
Device-2: Intel WiFi Link 5100 driver: iwlwifi v: kernel port: e000
bus ID: 02:00.0 chip ID: 8086:4232
IF: wlp2s0 state: up mac: <filter>
Device-3: Atheros TP-Link TL-WN821N v3 / TL-WN822N v2 802.11n [Atheros
AR7010+AR9287]
type: USB driver: ath9k_htc bus ID: 1-3:3 chip ID: 0cf3:7015
IF: wlxf8d1116651df state: down mac: <filter>
Drives:
Local Storage: total: 4.66 TiB used: 1.30 TiB (27.9%)
ID-1: /dev/sda type: USB vendor: Seagate model: Expansion Desk
size: 1.82 TiB serial: <filter>
ID-2: /dev/sdb vendor: Kingston model: RBUSMS180DS3128GH size: 119.24 GiB
speed: 6.0 Gb/s serial: <filter>
ID-3: /dev/sdc type: USB vendor: Seagate model: Expansion Desk
size: 1.82 TiB serial: <filter>
ID-4: /dev/sdd vendor: Seagate model: ST1000LM035-1RK172 size: 931.51 GiB
speed: 6.0 Gb/s serial: <filter>
Optical-1: /dev/sr0 vendor: HP model: DVD Writer 557s rev: QH22
dev-links: cdrom,cdrw,dvd,dvdrw
Features: speed: 8 multisession: yes audio: yes dvd: yes
rw: cd-r,cd-rw,dvd-r,dvd-ram state: running
Partition:
ID-1: / size: 116.87 GiB used: 51.62 GiB (44.2%) fs: ext4 dev: /dev/sdb1
Sensors:
System Temperatures: cpu: 38.0 C mobo: N/A
Fan Speeds (RPM): N/A
Info:
Processes: 239 Uptime: 35m Memory: 15.55 GiB used: 5.59 GiB (35.9%)
Init: systemd v: 237 runlevel: 5 Compilers: gcc: 7.5.0 alt: 7 Shell: bash
v: 4.4.20 running in: gnome-terminal inxi: 3.0.32

I tried every which way with the cables. First, I had both cables plugged into the sockets on the back of my computer, 1 x HDMI & 1 x DP1. I have 3 sockets on the monitor, 1 x multi-pin plug and 2 x HDMI sockets. I tried the DP1 first and it works just fine, I then removed the DP1 cable and fitted the HDMI cable, rebooted and got a blank screen. If I fit both cables to the monitor and computer and reboot I get no desktop icons and no icon bar at the bottom of the screen. Removed the HDMI cable, refitted the DP1 cable, rebooted and all the icons plus bar reappear. The DP1 cable has an extension to fit the multi-pin socket that screws into the monitor.

Gael

Have you switched the input on the monitor from DP to HDMI?

There is no physical switch on the monitor itself, however, in "settings" there is a way to switch from DP1 to HDMI ... sadly, it didn't work.

Gael

Ok, and did you try (as suggested previously), powering off your PC and the monitor (after setting the monitor to HDMI), plugging in HDMI, and then powering the monitor on FIRST, then the computer???

And posting the inxi info is great...except it'd be far better to say something like "I have a <Brand><Model> laptop with <Graphics Chip>", or something along those lines. What kind of video hardware do you have? What driver are you using?? Brand/model computer???

Okay, Does it make a difference between turning the computer & monitor off and pulling the plugs from there sockets? I ask because I only switched off on the devices and not at the electricity sockets.

The computer is a fanless mini computer Eggsnow Fanless Core i7 Mini PC Desktop Computer with Intel Core i7 6500u 2.5Ghz 16GB RAM 128GB SSD 1Tb HDD 300M Wifi Graphics:
Device-1: Intel Skylake GT2 [HD Graphics 520] driver: i915 v: kernel
bus ID: 00:02.0 chip ID: 8086:1916
Display: x11 server: X.Org 1.19.6 driver: modesetting unloaded: fbdev,vesa
resolution: 1920x1080~60Hz
OpenGL: renderer: Mesa DRI Intel HD Graphics 520 (Skylake GT2)
v: 4.5 Mesa 19.2.8 compat-v: 3.0 direct render: Yes

gael

GPUs and Displays are not intended for being connected to each other with more than one cable at a time. That you did this might have caused a component failure inside the BenQ.

When a new display is shipped with only one type of cable, it suggests a preferred method of connectivity. You might only now have a failed BenQ, or a BenQ defective as received. I would contact your BenQ vendor and/or BenQ warranty support simply to say the DP works but the HDMI does not.

Have you confirmed your HDMI cable works with anything else?

Can you connect your BenQ to any other output device via HDMI and have it work?

Do you have some particular need to use HDMI rather than DP?

I always use DP rather than HDMI if both are present and available, and both work.

As already mentioned, order of power up, and power up timing, can make a difference. Powering up the PC before the display is an invitation for inexplicable failure. It shouldn't be, but here, with multiple PCs sharing fewer and various displays, it occasionally is. I have one combination somewhat like you describe but reversed - HDMI always works, but DP sometimes does not, unless boot is allowed to proceed blindly through POST and Grub menu - when KMS kicks in, the display via DP, only to a UEFI PC, will light up as if nothing was wrong with anything. Connected to a legacy BIOS PC, its DP works normally from the outset.

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Okay, since I have time on my hands because of the CV-19 pandemic I did as was suggested and checked if I could obtain the correct users manual. Yes, I found it and downloaded it and read it very carefully. My old University teacher had a saying, he knew about human nature and our tendency to take shortcuts. He said, "When all else fails, read the instructions." Not for the first time in my fairly long life, I'm 74, I have like most other people played with a problem thinking that we will crack it without having to read through reams of paperwork. Well, I guess there is no fool like an old fool for after I had read through the manual it took me less than two minutes to solve the problem. Lesson learned. the solution is that one should make every effort to obtain the user manual and follow the instructions. I know that there will be times when a manual is not available, but the lesson I have learned is that it is prudent to attempt to get the user manual and importantly read it through. I have discovered that most (if not all) hardware either comes with a manual or can easily be got from the website. This was my failing and I am sorry to all you guys for asking for your help when the clearest of help was there in the form of a well put together user manual. All I can say is 'sorry' and thank you all for your help and tolerance.

Thanks to everyone who pointed me in the right direction.
Feeling slightly embarrassed,

Gael

and the problem's solution was???

1 members found this post helpful.

OP: please post the solution so that others who potentially be in the same situation can benefit from what you learned.