cancel
Showing results for 
Search instead for 
Did you mean: 

Drivers & Software

joevt
Adept I

W5700 DSC support

I have a Radeon Pro W5700. It has DSC support in macOS 10.15.7 but I'm not sure about Windows 10. Which drivers for Windows 10 support DSC for the W5700?

I have four DisplayPort 1.4 devices that can support DSC:

1) Apple USB-C Digital AV Multiport Adapter (2 lanes DisplayPort 1.4 with DSC)
2) Club-3D CAC-1085 (4 lanes DisplayPort 1.4 with DSC)
3) CalDigit SOHO (uses the Synaptics VMM5210) (2 lanes DisplayPort 1.4, with MST, DSC)
4) Delock 87737 (uses the Synaptics VMM5330) (4 lanes DisplayPort 1.4, with MST)
5) HP Thunderbolt Dock G2 (uses the Synaptics VMM5330)  (2 lanes (via USB-C) or 4 lanes (via Thunderbolt) DisplayPort 1.4, with MST)

In macOS, I can only get #1 and #3 to do DSC. I can tell when DSC is enabled by using the AGDCDiagnose command. It shows the DPCD registers, connection bandwidth (link rate and lanes), and pixel color space and format.

For #2, I don't have a HDMI 2.1 display to test DSC.

The last three are MST hubs. The Delock is supposed to support DSC but it doesn't seem to get enabled. DPCD reports no DSC support which might mean that it doesn't have the latest firmware. The HP when I bought it said it was "DSC Ready" which suggests that a firmware update is required to enable DSC. I haven't tried the latest firmware yet.

#1 might having working DSC in Windows, since it says it's outputting 4K 60Hz 135KHz at 4:4:4 8bpc which I believe is an HDMI 2.0 timing of 594 MHz (based on the horizontal scan rate reported by the display) which cannot be done with two lanes of HBR3 without DSC (the max would be 540 MHz). But I don't see any explicit indication of DSC support in the AMD Radeon Software. The AMD Radeon Software reports the pixel clock as 593400 kHz which seems strange (should be 594 Hz).

So maybe the Windows drivers support DSC for SST but not MST? The CalDigit SOHO can also do HDMI 2.0 at 4K 60Hz 135KHz at 4:4:4 8bpc. So maybe DSC works for MST as well in that case at least. But I can't get 4K60 10bpc from the DisplayPort port of the CalDigit. I can select 10bpc but after a second it goes back to 8bpc. I tried creating a custom resolution 3840x2160 60Hz CVT-RB timing but if I try to select anything greater than 6bpc, it goes back to 6bpc. 8bpc should be doable at 533.25MHz even without DSC.

The Radeon software has poor support for DSC, MST, and multi-tile displays. They may work, but it doesn't show that they are being used. Intel Graphics Control Panel has an option to show MST topology at least. And for some reason the Radeon software doesn't have an option to change the resolution and refresh rate - I have to switch to a different app to change the resolution and refresh rate. And I don't understand why enabling GPU scaling removes the Color Depth and Pixel Format options.

I am trying to prove that the Delock doesn't support DSC like its product page says it should, but I can't get DSC to work properly with the CalDigit to prove the problem is not the GPU.

Tags (3)
0 Likes
19 Replies
elstaci
MVP

Re: W5700 DSC support

Probably the one person at AMD Forums that can answer your question concerning AMD Professional GPU cards is @fsadough .

0 Likes
fsadough
Moderator
Moderator

Re: W5700 DSC support

I have a Radeon Pro W5700. It has DSC support in macOS 10.15.7 but I'm not sure about Windows 10. Which drivers for Windows 10 support DSC for the W5700?

  • All available drivers

1) Apple USB-C Digital AV Multiport Adapter (2 lanes DisplayPort 1.4 with DSC)
2) Club-3D CAC-1085 (4 lanes DisplayPort 1.4 with DSC)
3) CalDigit SOHO (uses the Synaptics VMM5210) (2 lanes DisplayPort 1.4, with MST, DSC)
4) Delock 87737 (uses the Synaptics VMM5330) (4 lanes DisplayPort 1.4, with MST)
5) HP Thunderbolt Dock G2 (uses the Synaptics VMM5330)  (2 lanes (via USB-C) or 4 lanes (via Thunderbolt) DisplayPort 1.4, with MST)

  • What are you using these hubs and adapters for?
  • What is your display (make and model)?
  • Please describe the exact connection from W5700 to your display 

The AMD Radeon Software reports the pixel clock as 593400 kHz which seems strange (should be 594 Hz).

  • The report on AMD Radeon Software originates from the display/cable/hub/adapters. You see whatever is being received. 

But I can't get 4K60 10bpc from the DisplayPort port of the CalDigit.

  • I get 4K60Hz@10bpc on my side with no issues.

 

  1. Please provide an EDID report and AMDZ-Report

    AMDZ Report
    - Please extract the amdz-v285.zip
    - Run amdz.exe file as an Administrator
    - Select “Save All“ and “HTM“ as the output format
    - Click on the blue button to save the report
    - The .htm file will be saved in the same folder where you extracted the zipped file
joevt
Adept I

Re: W5700 DSC support

Right now I'm not using the hubs and adapters for anything. The W5700 has no HDMI outputs, so the HDMI functionality of adapters #1, #2, and #3 would be useful. The W5700 has plenty of DisplayPort outputs for DisplayPort functionality. The MST functionality is not useful because the W5700 already has 6 outputs and most GPUs can't do more than that even with MST (in other words, an MST hub won't let you connect two displays to a single port if the other 5 ports already have a display).

Basically, I am using the W5700 with these adapters to test situations where the DSC and MST support would be most useful - such as a PC laptop containing an AMD Navi dGPU with limited display output ports.

My test displays (none have DSC):
1) Acer XV273K - DisplayPort 1.4 4K120, also has a dual cable 4K144 mode, HDMI 2.0 4K60. Each input port is connected and operational even while the current input is set to a different port.
2) Dell UP2715K - DisplayPort 1.2 5K60 dual cable display
3) Dell P2415Q - DisplayPort 1.2 and HDMI 2.0 4K60 (only testing DisplayPort of this one)

I've included two AMDZ reports at https://we.tl/t-tN1bKa1ODx (filename amdz-joevt.zip)

report 1: W5700 Mini DisplayPort -> Delock -> XV273K DisplayPort, XV273K DisplayPort, P2415Q DisplayPort - all running at 4K30 8bpc but with DSC I would expect all three to be able to do 60Hz 8bpc.

report 2: W5700 Mini DisplayPort -> Delock -> XV273K DisplayPort 4K60 12bpc;  W5700 USB-C -> CalDigit -> XV273K DisplayPort 4K60 8bpc 594MHz but with DSC I would expect the CalDigit to allow at least 10bpc (but I think 8bpc 594Mhz requires DSC already)

In either case, the Dell UP2715K is also connected (dual cable mode 5K60 10bpc).

You say you get 4K60Hz 10bpc but is that 4:4:4/RGB from a USB-C hub having two lanes of DisplayPort 1.4?

What method do you recommend for getting the EDIDs? Windows methods seem to be unreliable - they sometimes only get 1 or 2 blocks instead of all the blocks. AGDCDiagnose in macOS will get all the blocks (the Apple Pro Display XDR can have 7 blocks depending on the situation).

0 Likes
fsadough
Moderator
Moderator

Re: W5700 DSC support

Keep in mind for DSC you need either DP 1.4 and up or HDMI 2.1 and up. I never tested a USB-C hub but DP 1.4

https://blogs.synopsys.com/vip-central/2018/04/24/10k-resolution-at-120hz-display-a-reality-today-wi...

EDID: Radeon Pro Settings => Settings => Display => Adjust EDID Settings => Open Radeon Pro Settings=> Select the proper Connection => Export EDID

fsadough_0-1612780178187.png

 

 

0 Likes
joevt
Adept I

Re: W5700 DSC support

I have uploaded EDIDs for 3 of my displays to:
https://we.tl/t-wcvLvwLCCM

The P2415Q has a HDMI 2.0 and DP 1.2 input.
The XV273K has two HDMI 2.0 and two DP 1.4 inputs (not DSC) but I think I only used three of the inputs.
The UP2715K has two DP 1.2 inputs.

I think what would be more useful than EDID is a dump of the DPCD registers for each DisplayPort device (MST Hub and display).

All three of my MST hubs are DisplayPort 1.4. At least one of them (the CalDigit) supports DSC. An MST Hub can convert a fast and narrow DisplayPort MST signal (HBR3 x2) to a slow and wide DisplayPort SST signal (HBR2 x4) (like a PCIe switch can convert PCIe 3.0 x4 to PCIe 2.0 x8 or x16). An MST Hub that supports DSC can take compressed input and decompress it for a display that does not support DSC. With DSC, a three port 4 lane DisplayPort 1.4 MST Hub can output three 4K60 8bpc DisplayPort 1.2 signals (38 Gbps total; 48 Gbps for 10 bpc - I don't know if DSC is good enough to allows 10 bpc for the three 4K60 displays). Without DSC, the limit is less than the input (HBR3x4 = 25.92 Gbps) - the limit allows two 4K60 8bpc displays (25.6 Gbps).

The CalDigit only has a HBR3x2 input = 12.96 Gbps because it's a USB-C hub that supports USB 3.x (there exists USB-C hubs that support USB 2.0 only and therefore have 4 lane DisplayPort input). With DSC, the CalDigit should be able to do two 4K60 8bpc displays (25.6 Gbps; 10 bpc requires 32 Gbps which exceeds the max allowed by a 2:1 compression ratio but is still less than 3:1 compression ratio but I don't think DSC on MST Hub can do 3:1? - I'm not even sure about 2:1, at least in the case of a MST hub). The product page doesn't mention DSC. Without DSC, two 4K30 8bpc displays can be supported (12.6 Gbps).

https://www.synaptics.com/products/video-interface-ics
https://uploadcdn.oneyac.com/attachments/userfile/b4/13/1593672494627_4765.pdf

0 Likes
fsadough
Moderator
Moderator

Re: W5700 DSC support

Both are Navi boards W5500and W5700 support DSC.

I cannot comment on DSC support on the MST hubs, specially CalDIGIT claiming to be able to convert non-DSC to DSC. Please contact their support line for further investigation. We do not validate the functionality of  MST hubs.

0 Likes
joevt
Adept I

Re: W5700 DSC support

DSC and MST are part of the DisplayPort 1.4 spec. Do you not support both those features of the spec?

In macOS 10.15.7, I can't seem to get 10 bpc and DSC to work at the same time. macOS doesn't have a bpc option but the HDR option that it does have will use 10bpc. Since I can't use 10bpc with DSC, the only other way to increase bandwidth to force the use of DSC is to increase the number of pixels per second - either by using a higher resolution or a higher refresh rate. The W5700 can do 4K 114Hz 8bpc RGB (HBR3 x4) from the CalDigit SOHO DisplayPort output using DSC through the input (HBR3 x2).

I went back to Windows, to try the same thing. There is some strange behavior for various 3840x2160 refresh rates. AMD Radeon Software Custom Resolutions only allows 10 custom resolutions which makes testing of different refresh rates difficult. Plus it applies the changes after every change which causes the screen to flash so it takes 5 seconds to make each change. SwitchResX in macOS is a much better experience - changes don't take affect until applied manually so they can be edited quickly.

Below is a list of behaviours for a XV273K connected to DisplayPort output of CalDigit SOHO connected to USB-C port of W5700:
built-in timings:
23Hz, 24Hz, 29Hz 297Mhz; 30Hz 263MHz: 6, 8, 10, 12bpc all work.
50Hz, 59Hz, 60Hz 594MHz: 6bpc and 8bpc works; 10bpc goes to 8bpc.

CVT-RB custom timings:
25Hz 219MHz - 57Hz 506MHz: 6bpc works; 8bpc, 10bpc, and 12bpc goes to 6bpc.
58Hz 515MHz - 68Hz 607MHz: 6bpc works; 8bpc and 10bpc goes to 6bpc.
69Hz 616MHz - 76Hz 681MHz: 6bpc works, 8bpc goes to 6bpc.
77Hz 690MHz - 83Hz 746MHz: 8bpc black screen.
84Hz 755MHz - 115Hz 1049MHz: 8bpc vibrating screen (image moves vertically up and down a few pixels rapidly) 
116Hz 1059MHz: not listed.

So it seems that the Windows AMD driver can do DSC with the MST Hub but there are issues with the 6bpc refresh rates, the black screen refresh rates, and the vibrating screen refresh rates.

I was able to update the firmware of the HP Thunderbolt Dock G2 (requires non-DCH Thunderbolt driver). This enables The DSC capability of its internal 3 port DisplayPort 1.4 MST Hub. I can connect the HP Thunderbolt Dock G2 via USB-C to the W5700. This means it uses two lanes of HBR3 like the CalDigit SOHO and the 4K refresh rates have the same behavior as listed above.

I can enable a four lane HBR3 connection between the HP Thunderbolt Dock G2's MST Hub and the W5700 using a GC-TITAN RIDGE. The black screen refresh rates are no longer black screen. But I still can't do custom refresh rates at anything other than 6bpc... Maybe I need to use CRU to create custom resolutions (but I think CRU limits the max number of EDID extension blocks so it may be inefficient for testing many custom refresh rates).

A four lane 3 port DisplayPort 1.4 MST Hub with DSC should be able to do three 4K60 displays. I think this works. I had issues (maybe DisplayPort link training is not working will with this chain of devices: W5700, GC-TITAN RIDGE, HP Thunderbolt Dock G2 internal MST Hub, 3 displays; which causes Radeon Software to timeout/crash sometimes) but restarting seems to make it work better.

I still need to convince Delock that my 87737 doesn't have the firmware required for DSC support - otherwise I would use that for four lane HBR3 MST DSC tests.

All tests use the 20.Q4 2021-02-05 drivers.

0 Likes
fsadough
Moderator
Moderator

Re: W5700 DSC support

DSC and MST are part of the DisplayPort 1.4 spec. Do you not support both those features of the spec?

Yes we comply with DP1.4 specifications. Please read my previous reply carefully. Your issue is related to MST hubs manufactured by various third-party companies.

I cannot comment on DSC support on the MST hubs, specially CalDIGIT claiming to be able to convert non-DSC to DSC. Please contact their support line for further investigation. We do not validate the functionality of MST hubs.

joevt
Adept I

Re: W5700 DSC support

I don't understand your argument about not validating MST functionality because hubs are manufactured by third-party companies. You don't say the same about displays, do you? I'm sure testing has been done in the past with various displays and MST hubs.

My tests in my previous post confirm that the CaDigit and HP hubs convert DSC input to non-DSC output (at least given the info provided by the Radeon Software and the info in Windows: "Settings" -> "Display" -> "Advanced display settings"). My comments apply to the Radeon driver's ability to output the correct signals. It appears that the Windows driver does support DSC+MST functionality but has issues with some refresh rates in combination with some MST hubs. Maybe you can tell by the ranges of pixel clocks if there are edge cases where the driver may be making an incorrect decision. I wonder if the Windows driver sends an SST or MST signal to an MST hub when only one display is connected? That could make a difference.

I removed the MST hubs to verify the issues are MST or not MST related. I tried all my custom resolutions (57Hz, 68Hz, 76Hz, 83H, 115Hz, 116Hz) created using the Radeon software. They all work (no black or vibrating screen) but they all only allow 6bpc as before. If I select 8bpc, 10bpc, or 12bpc, it goes back to 6bpc. The native timings (including 120Hz) allows 6bpc and 8bpc as expected. 120Hz also shows a 10bpc and 12bpc modes but if they're selected, it goes back to 8bpc. They can be used after 4:2:2 is first selected (what might be cool is if an option (like bpc) that requires a change in another option (pixel format or refresh rate) is displayed in a different color). All bpc can be used when the refresh rate is the native 60Hz. So there is some issue with custom resolutions that is not MST related.

I guess I could try using CRU to create the custom resolutions to see if they behave better than the ones created in the Radeon Software.

0 Likes