Lenovo 40as Driver Download

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Piperion Giles

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Aug 3, 2024, 4:53:46 PM8/3/24

to malritalo

Since most of my MST equipment is using Synaptics chips, on Windows I can get by with just using Synaptics debugging tool, that shows a ton of details about its own MST-Chips and their current connection.

And in my experience with Intel iGPUs, linux has instability and problems with MST and HUGE problems with DSC, which all of those docks support and under Windows use to get to the max capabilities.
I think you are already looking in the right place. The only thing I have come across was /sys/kernel/debug/dri/0/amdgpu_dm_dtn_log, as developers requested that when debugging the AMD driver white flicker issues on RDNA3 with 64GB memory and more and it seems to show a bunch of details about the display pipelines. But no MST topology.

Edit: Might be worthwhile to reverse engineer how the Synaptics VmmDpTool communicates with its chips. Is there some generic API to access / read DPCD registers? Or is that using some GPU-specific API to establish a custom link to its chips?

Edit2:
Also, outside of Apple, you should expect any MST-device being connected via MST, always. Even if it does not provide any benefit at the moment (i.e. only a single stream used). Using an SST connection on a MST-Hub should lead to the same exact data being output on every possible output at the same time and the MST-Hub picking an attached monitor at random to represent as the single monitor to the host.

On an Ubuntu Live USB it works out of the box, on Windows 10 you have to install the AMD drivers manually (not the framework driver pack). Have not tried Windows 11.
In any case you will probably have to update the dock firmware.

The 40AC Gen1 TB3 dock is older. According to Lenovos resolution tables, it supports neither HBR3 nor DSC, so it might include an older chip than the VMM53xx that is used in almost all other docks like it.

Given the similarity of the output between Intel and AMD, I would expect them both to share some amount of code with respect to MST. Although I do not know if that includes the policy part that decides over bandwidth allocation and DSC or if it is just the modelling of the resulting decisions that are described by that debugging option.

Appreciate the discussion here. Currently eyeing the lenovo 40AS as my docking station of choice, though the HP gen5/gen2 dock is tempting as well. Has anyonw by chance heard something about the HP one? I read that at least displaylink is hit or miss on linux

I have a CalDigit TS4 and everything works fine, including 4k@144hz (AMD Ryzen, 3.03 BIOS, Fedora 39). The only thing which does not work is booting and shutting down while connected, because the OS will hang forever. This means I have to unplug my Framework from the dock, boot to Desktop and only then connect.

As I had a similar issue on a 6800u based Laptop, how would I go about testing this? Compile a custom kernel? If there is some documentation somewhere around this, a simple pointer would also be very much appreciated