hdmi interview questions

Top hdmi frequently asked interview questions

Does DisplayPort carry sound as HDMI does?

Does DisplayPort carry sound as HDMI does? Specifically, I am looking at Lenovo Laptops T410 or T510.

I'm wondering if the spec permits for audio over DP and if possible if the Lenovo laptops I mentioped implement it.

Source: (StackOverflow)

Is HDMI hot pluggable?

I'm trying to connect my laptop (Dell XPS 17 L702X) to a TV via HDMI. In the process I've hot-plugged the cable several times, but to no avail. Could this damage the HDMI port on my laptop or TV?

Source: (StackOverflow)

Does the HDMI port on a video card support audio?

When purchasing a video card based on nVidia or AMD, does the HDMI port support audio as well as video?

For what it's worth, I'm running Xubuntu 14.04.

Here's an example of a video card with built-in HDMI:

Please note, that is just an example, please do not flag this as a shopping question!

Source: (StackOverflow)

Triple monitor setting in Linux with USB-HDMI adapter

I'm trying to set up a triple monitor desktop at my office using Fedora 17, but it seems impossible, let me explain the setting:

  • Laptop ASUS K53SD with 2 graphic cards, Intel and nVidia (Screen controled by Intel card)
  • 24" Full HD monitor connected to the HDMI output (controlled by Intel card)
  • 23" Full HD monitor connected to an USB-HDMI adapter (via framebuffer in /dev/fb2, apparently)
  • VGA output (not used) controlled by nVidia card

First of all, the USB-HDMI adapter works perfectly, it gives me a green screen (which means the communication is OK) and I can make it work if I set up a single monitor setting via framebuffer in Xorg. Here I leave the page where I got the instructions:

Now I'm trying to set up the the two main monitors (laptop and 24") with the intel driver and the 23" with the framebuffer, but the most succesful configuration I get is the two main monitors working and the third disconnected.

Do you have any idea what can I do to make this work?

Here I leave my xRandr output and my Xorg conf:

-> xrandr
Screen 0: minimum 320 x 200, current 3286 x 1080, maximum 8192 x 8192
LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1366x768       60.0*+
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA2 disconnected (normal left inverted right x axis y axis)
HDMI1 connected 1920x1080+1366+0 (normal left inverted right x axis y axis) 531mm x 299mm
   1920x1080      60.0*+   50.0     25.0     30.0  
   1680x1050      59.9  
   1680x945       60.0  
   1400x1050      74.9     59.9  
   1600x900       60.0  
   1280x1024      75.0     60.0  
   1440x900       75.0     59.9  
   1280x960       60.0  
   1366x768       60.0  
   1360x768       60.0  
   1280x800       74.9     59.9  
   1152x864       75.0  
   1280x768       74.9     60.0  
   1280x720       50.0     60.0  
   1440x576       25.0  
   1024x768       75.1     70.1     60.0  
   1440x480       30.0  
   1024x576       60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   720x576        50.0  
   848x480        60.0  
   720x480        59.9  
   640x480        72.8     75.0     66.7     60.0     59.9  
   720x400        70.1  
DP1 disconnected (normal left inverted right x axis y axis)
   1920x1080_60.00   60.0  

The Xorg file:

# Xorg configuration file for using a tri-head display

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "HDMI" 0 0
    Screen      1  "USB" RightOf "HDMI"
    Option         "Xinerama" "on"

########### MONITORS ################

Section "Monitor"
    Identifier     "USB1"
    VendorName     "Unknown"
    ModelName      "Acer 24as"
    Option         "DPMS"

Section "Monitor"
    Identifier     "HDMI1"
    VendorName     "Unknown"
    ModelName      "Acer 23SH"
    Option         "DPMS"

########### DEVICES ##################

Section "Device"
    Identifier     "Device 0"
    Driver         "intel"
    BoardName      "GeForce"
    BusID          "PCI:0:02:0"
    Screen          0

Section "Device" 
    Identifier     "USB Device 0" 
    driver         "fbdev" 
    Option         "fbdev" "/dev/fb2" 
    Option         "ShadowFB" "off"

############## SCREENS ######################

Section "Screen"
    Identifier     "HDMI"
    Device         "Device 0"
    Monitor        "HDMI1"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24

Section "Screen"
    Identifier     "USB"
    Device         "USB Device 0"
    Monitor        "USB1"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24

Source: (StackOverflow)

HDMI vs Component vs VGA vs DVI vs DisplayPort

What are the pros and cons of each of these different display adapters and cables?

From what I can understand, HDMI offers the ability to send audio along the same cable as well as the ability to do progressive scan.

I've Googled but I can't seem to find any real answers. Why would someone care to run 1280x1024 over HDMI or DVI instead of VGA? What about component?

All I hear is one is digital and one is analog, but I can't find what that means from a feature/benefit stand point.

Source: (StackOverflow)

Cleaning computer cables In the dishwasher

A large quantity of assorted computer cables came into my possession. The collection includes almost every type of computer-related cable (video, USB, Ethernet, printer, audio and speaker, SATA, power, etc.). I'm focused here on just passive cables, nothing with active electronics or things like power bricks. They became dirty in storage and need to be cleaned.

Most of us have probably heard about washing a keyboard in the dishwasher, and now I am wondering if the same method can be applied to dirty cables. My assumption is that because the older PS2 keyboards used in these dishwashing experiments have their own cables attached, what could be the difference?

Some of the possible concerns I can envision with using a dishwasher to clean them:

  • Cable construction could be different from a keyboard cable and the materials and fastenings might not hold up to dishwasher cleaning.
  • Dishwasher water temperature might be too hot for the materials used in some kinds of cables.
  • Immersing some kinds of cables in water might be bad for them, so some might be cleanable in a dishwasher and some not.

My assumption is that if all kinds of cables cannot be safely cleaned in this way, cables fall into just a few broad categories that drive what would be dishwasher-safe.


  1. Dishwashability

    What characteristics (for example, type of construction or type of use), would differentiate computer-related cables that should not be cleaned in a dishwasher, and why?

  2. Scope of risk

    If a computer cable is put through the dishwasher and is adversely affected in a way that isn't externally visible (so it would be used rather than discarded), would it be only the cable that was affected? Or, is there any kind of computer cable where the kinds of adverse effects that could come from cleaning in a dishwasher could damage the equipment it's plugged into?

Source: (StackOverflow)

HDMI with resolution 2560 x 1440 possible?

I have an Acer 1810T and am going to buy a Dell u2711 with a resolution of 2560 x 1440.

Can I connect the panel over HDMI with the Acer and use the 2560 x 1440 res?

Source: (StackOverflow)

Maximum resolution through VGA/DVI/HDMI(/etc)?

I know the original VGA standard was meant to output 640x480 and that other standards over the original VGA connector are developed to output a higher resolution. (SVGA, XGA, etc.) But I was wondering if there's a specific limit to the resolution that the VGA connector can take.

Furthermore, are, and if so how are for example DVI and HDMI limited on resolution?

Source: (StackOverflow)

Is there any benefit of using HDMI over DVI?

I recently bought a Mac mini. It comes with an HDMI to DVI adapter. I bought a LG monitor that has an HDMI port.

My concern is: Is there any improvement when I connect the Mac Mini to the monitor using an HDMI cable?

Currently I am connecting to the monitor's DVI port via the adapter and it is working fine. I need to know whether there's any difference in using the HDMI port directly.

Source: (StackOverflow)

Is it possible to power on/off a monitor using the computer?

I was wondering if it was possible to power on/off a display using a computer connected via HDMI. Let me explain :

I want my computer to power off my monitors (not standby mode) when I don't use it (no keyboard/mouse input) for more than 15 minutes, and power them back when such input is received. My monitors are connected over HDMI, so I was wondering if it was possible to use the CEC functionality with a computer. If is it possible, then is there a hardware requirement ?

My point is that I often take a break from my computer, but forget to turn off the screens, and I would prefer to shut down the screens completely instead of putting them to standy mode

Thanks a lot

Source: (StackOverflow)

Does a HDMI-to-DVI (dual link) adapter exist? I don't care about the price

My monitor supports full-resolution display (2560x1440) only when connected to through either the DVI-D dual link port, or the DisplayPort.

My laptop, though, has neither of these two kinds of output. Instead, all it's got is a HDMI port (which is version 1.3, and I also read that the laptop's graphics chipset supports 2560x1440 at 60Hz).

So I'm wondering whether anyone has ever seen an HDMI-to-DVI dual link adapter, which will carry my ultra-highres signal to the monitor I just bought. So far I haven't seen any, and don't even know whether such an adapter (which I understand would have to be active, USB-powered and expensive (but I don't care)) exists.

Source: (StackOverflow)

Converting DisplayPort and/or HDMI to DVI-D?

Newer Radeon video cards come with four ports standard:

  • DVI (x2)
  • HDMI
  • DisplayPort

enter image description here

If I want to run three 24" monitors, all of which are DVI only, from this video card -- is it possible to convert either the HDMI or DisplayPort to DVI? If so, how? And which one is easier/cheaper to convert?

I did a little research and it looks like there isn't a simple "dongle" method. I found this DisplayPort to DVI-D Dual Link Adapter but it's $120; almost cheaper to buy a new monitor that supports HDMI or DisplayPort inputs at that point!

There's also a HDMI to DVI-D adapter at Monoprice but I'm not sure it will work, either.

AnandTech seems to imply that you do need the DisplayPort-to-DVI:

The only catch to this specific port layout is that the card still only has enough TMDS transmitters for two ports. So you can use 2x DVI or 1x DVI + HDMI, but not 2x DVI + HDMI. For 3 DVI-derived ports, you will need an active DisplayPort-to-DVI adapter.

Source: (StackOverflow)

How to stop windows resizing when the monitor display channel is turned off / switched to different source

I have a new 6870 Amd Radeon adapter with its drivers set to 1080p 60Hz resolution hooked up to a 2008 47" high end Samsung HDMI based TV.

However, when the tv is turned to a different HDMI input -(when I come back into windows) somehow Windows decides to resize all the open apps to a lower resolution - including some of the side docked hidden pop-outs. When it resizes those though - it just sticked the pop-outs in the middle of the screen and all the resized windows from the open applications in the top left corner - all of them stacked on top of each other and resized to the smaller resolution.

The things that seem to be ok after returning are the icons on the desktop, the taskbar, and the sidebar.

Anyone have any knowledge of 1) how this happens 2) why it happens 3) how to stop it from resizing the applications and some of the docked pop-outs (they are not really resized after returning - they are just stuck in the middle of the screen approximately where they would be if the right or bottom sidebar should be if the screen was resized to that lower resolution).

My hypothesis is that upon losing HDMI signal - that Windows is told by something (driver, or windows itself) that the resolution to be without a signal being present (noting that HDMI signals and handshakes are two way on HDMI devices. If it loses the signal or the tv is switched to another device - then the display adapter must figure that out and tell Windows or figures it out and designs randomly to change the display size).

Any and all help is most appreciated. I asked AMD/ATI - but they said they don't know why or how this is happening. I was hoping that maybe this is THE place that the super users truly go to - those that develop display adapter drivers, or that dive deeply into these areas of windows. If there is better sites or just competing sites - please advise - noting I have already written AMD/ATI.

Response / Additions 4/7/2011

It is really nice to get your reply Shinrai. (BTW is it proper etiquette on these forums to have a discussion?) Yet 'only one issue' - I am using a single display in this case - so Windows doesn't move application windows to another desktop. Windows (or something) decides to shrink the desktop it currently has and resize all windows to the maximum size of the desktop. As such I would be glad if Windows would just keep the current size of the one desktop that is in operation.

I also know that this does NOT happen on monitors connected with DVI. There I have had one and two monitors setup and it doesn't resize those screens at all when disconnecting monitors, turning them off, whatever... they stay solid - everything in place - to such an extent that if you forgot the other monitor is off - you will have troubles finding some windows without using one of the control app utilities.

So if I could even get the HDMI handling by Windows (or the display driver) ( 1] which is doing this anyway the display driver or Windows - and 2] where is that other resolution size (1024x768) coming from - its not the smallest and its not the largest?) to be having like DVI - Life would be golden (for this aspect anyway).

** found others with same problem in this thread:

Source: (StackOverflow)

Connecting a 2560x1440 display to a laptop?

Having read Jeff Atwood's blog post on Korean 27" IPS LCDs, I've been wondering to what extent these are useful in a notebook + large display situation.

I own a Lenovo Thinkpad Edge E320 with 2nd gen. integrated Intel graphics. According to the spec from Intel, this should support HDMI version 1.4, and, using DisplayPort, resolutions up to 2560x1600. HDMI version 1.4 supports resolutions up to 4096×2160, however, according to c't (German), the HDMI interface used with Intel chips only supports 1920x1200. The same goes for the DVI output - dual-link DVI-D, apparently, is not supported by Intel.

It would appear that my laptop cannot digitally drive this kind of resolution. Now what about other laptops?

According to the article in c't above, AMD's integrated graphics chips have the same limitation as Intel's.

NVIDIA graphics cards, apparently, only offer resolutions up to 1900x1200 over HDMI out of the box, but it's possible, when using Linux at least, to trick the driver into enabling higher resolutions. Is this still true? What's the situation on Windows and OSX?

I found no information on whether discrete AMD chips support ultra-high resolutions over HDMI.

Owners of laptops with (Mini) DisplayPort / Thunderbolt won't have any issues with displays this large, but if you're planning to go for a display with dual-link DVI-D input only (like the Korean ones), you're going to need an adapter, which will set you back something like €70-€100 (since the protocols are incompatible).

The big question mark in this equation is VGA: a lot of laptops have it, and I don't see any reason to think this resolution is not supported by the hardware (an oft-quoted figure appears to be 2048x1536@75Hz, so 2560x1440@60Hz should be possible, right?), but are the drivers likely to cause problems?

Perhaps more critically, you'd need a VGA to dual-link DVI-D adapter that converts analog to digital signals. Do these exist? How good are they? How expensive are they? Is there a performance penalty involved?

Please correct me if I'm wrong on any points.

In summary, what are the requirements on a laptop to drive an external LCD at 2560x1440, in particular one that supports dual-link DVI-D only, and what tools and adapters can be used to lower the bar?

Source: (StackOverflow)

I don't have a monitor; how to play copy-protected content?

Let me preface this with the fact that I am totally blind so do not have a monitor hooked up to my computer.

I have a cable card tuner that I would like to use to record and play TV shows. It appears that I can record anything I want but cannot play it back if it has the copy protection flag set since I don’t have a monitor hooked up to my computer.

What can I do that will allow me to play back copy-protected content?

Source: (StackOverflow)