3 ms·

Most TVs don't have DisplayPort

by tapoxi 5mo ago

cassianoleal 5mo ago
An adaptor costs £7.
- amlib 5mo ago
  They have limitations, specially when driven to the limits of the specifications. When doing 4k@120fps 4:4:4 chroma you might have to deal with longer handshakes and sometimes even no handshake at all. Or random dropouts. Or HDR not activating properly.
  - happyPersonR 5mo ago
    I thought handshakes were just when you were setting up a connection no? Random dropouts tho sound bad… with high speed signaling also sounds like a pain to figure out
- eliaspro 5mo ago
  But wouldn't this break the HDCP chain and therefore render many use-cases (playback of DRM-protected streams) broken?
  - cassianoleal 5mo ago
    Is that a problem for most uses of DP?
- tapoxi 5mo ago
  For HDMI 2.0. For HDMI 2.1 and 4K/120hz you're looking at north of $25 and don't get VRR support.
  - cassianoleal 5mo ago
    Fair enough about VRR, but £13 for 4k/240Hz - https://www.amazon.co.uk/dp/B0FQCF62CD https://www.amazon.co.uk/dp/B0FQCF62CD
    - redeeman 5mo ago
      with lossy compression
    - elabajaba 5mo ago
      I've owned 2 of these (returned and reordered thinking the first might've just been bad) and neither worked properly on Linux with an AMD 9070xt and an LG CX. They'd have black screen dropouts every few minutes, and occasionally full screen color corruption.
- AnthonBerg 5mo ago
  They are not equivalent. Conversion is a very intricate spec fulfilment over an incredibly high bandwidth signal. I did the dive; The adapters are not sufficient.
  - perching_aix 5mo ago
    In what way are they not sufficient?
    - charleslmunger 5mo ago
      The Synaptics VMM7100-based adapters only support VRR on older firmware versions with bugs. The Chrontel CH7218 is the most reliable but still also suffers blackouts during VRR. ParadeTech PS196 adapters advertise VRR support but their DPCD does not correctly communicate that it is supported. So even if you add the chip to the VRR PCON list in the amdgpu driver, it still won't see VRR as supported. And while some of these advertise themselves as displayport 2.0, all of them only support bandwidth of 25.96gbps on the displayport side, requiring DSC for 4k 120hz 10bit color, even though they support 48gbps on the HDMI output.
  - whazor 5mo ago
    Do you know whether HDMI CEC adapters impact the signal?
- preisschild 5mo ago
  There are only a few adapters that support the 2.1 features (hdr+vrr+high resolution+high refresh rate, no lossy DSC). I even had to flash custom firmware for most of those features to work (vrr still doesnt)
preisschild 5mo ago
In my case its an issue because I have a monitor with only a single DP port and I need to switch between my tower and laptop. I have to use HDMI for the laptop to monitor connection.
- chocochunks 5mo ago
  You can get DisplayPort KVMs. As a nice bonus the KVM will let you share a single mouse and keyboard set between them.
  - preisschild 5mo ago
    My monitor (Samsung Odyssey Neo G9) has a usb kvm built in, i can already do that. Plus I havent really seen an external dp2.1 kvm switch yet and I'm sure if they exist they are expansive.

Most TVs don't have DisplayPort

by tapoxi 5mo ago

Most TVs don't have DisplayPort

cassianoleal 5mo ago

An adaptor costs £7.

amlib 5mo ago
They have limitations, specially when driven to the limits of the specifications. When doing 4k@120fps 4:4:4 chroma you might have to deal with longer handshakes and sometimes even no handshake at all. Or random dropouts. Or HDR not activating properly.
- happyPersonR 5mo ago
  I thought handshakes were just when you were setting up a connection no? Random dropouts tho sound bad… with high speed signaling also sounds like a pain to figure out
eliaspro 5mo ago
But wouldn't this break the HDCP chain and therefore render many use-cases (playback of DRM-protected streams) broken?
- cassianoleal 5mo ago
  Is that a problem for most uses of DP?
tapoxi 5mo ago
For HDMI 2.0. For HDMI 2.1 and 4K/120hz you're looking at north of $25 and don't get VRR support.
- cassianoleal 5mo ago
  Fair enough about VRR, but £13 for 4k/240Hz - https://www.amazon.co.uk/dp/B0FQCF62CD https://www.amazon.co.uk/dp/B0FQCF62CD
  - redeeman 5mo ago
    with lossy compression
  - elabajaba 5mo ago
    I've owned 2 of these (returned and reordered thinking the first might've just been bad) and neither worked properly on Linux with an AMD 9070xt and an LG CX. They'd have black screen dropouts every few minutes, and occasionally full screen color corruption.
AnthonBerg 5mo ago
They are not equivalent. Conversion is a very intricate spec fulfilment over an incredibly high bandwidth signal. I did the dive; The adapters are not sufficient.
- perching_aix 5mo ago
  In what way are they not sufficient?
  - charleslmunger 5mo ago
    The Synaptics VMM7100-based adapters only support VRR on older firmware versions with bugs. The Chrontel CH7218 is the most reliable but still also suffers blackouts during VRR. ParadeTech PS196 adapters advertise VRR support but their DPCD does not correctly communicate that it is supported. So even if you add the chip to the VRR PCON list in the amdgpu driver, it still won't see VRR as supported. And while some of these advertise themselves as displayport 2.0, all of them only support bandwidth of 25.96gbps on the displayport side, requiring DSC for 4k 120hz 10bit color, even though they support 48gbps on the HDMI output.
- whazor 5mo ago
  Do you know whether HDMI CEC adapters impact the signal?
preisschild 5mo ago
There are only a few adapters that support the 2.1 features (hdr+vrr+high resolution+high refresh rate, no lossy DSC). I even had to flash custom firmware for most of those features to work (vrr still doesnt)

preisschild 5mo ago

In my case its an issue because I have a monitor with only a single DP port and I need to switch between my tower and laptop. I have to use HDMI for the laptop to monitor connection.

chocochunks 5mo ago
You can get DisplayPort KVMs. As a nice bonus the KVM will let you share a single mouse and keyboard set between them.
- preisschild 5mo ago
  My monitor (Samsung Odyssey Neo G9) has a usb kvm built in, i can already do that. Plus I havent really seen an external dp2.1 kvm switch yet and I'm sure if they exist they are expansive.