From Lwn · · 2m
Synaptics patent claims stop work on DisplayLink drivers
Synaptics patents block Linux driver development for DisplayLink docks.
In brief
Synaptics patents block Linux driver development for DisplayLink docks. Synaptics issued patent claims that stopped a Linux driver developer from improving DisplayLink dock compatibility. Originally reported by Lwn.
Patent claims stop driver work
Mike Lothian tried to improve DisplayLink dock drivers on Linux using LLM assistance but faced patent claims from Synaptics.
“If you have knowledge of the DisplayLink DL3 control-plane engagement sequence, or ideas for isolating a whole-bus timing/ordering property a per-channel diff cannot see, help would be very welcome”
DisplayLink dock issues
Lothian's dock crashed under Linux, so he developed a Rust-based driver called Vino to fix compatibility.
Synaptics legal response
Synaptics sent a cease-and-desist notice demanding Lothian stop driver development and withdraw submissions.
“The reason I'm writing is that DisplayLink is not an open standard. The protocol, codec, and other technologies used by DisplayLink devices are proprietary to Synaptics and are protected by a substantial portfolio of patents in a number of jurisdictions, including the UK”
Patent claims details
Synaptics listed 125 patents covering DisplayLink's architecture and demanded Lothian stop work by August 28.
OIN protection attempt
Lothian sought Open Invention Network help but OIN said their protections didn't cover codec implementations.
“OIN's conclusion was that, since codecs are explicitly not covered by OIN's Linux System Definition, its protections did not extend to Lothian's attempted kernel contributions”
Deadline extension
Lothian asked for deadline extension to October 18 after Synaptics claimed he was infringing patents.
Vino driver status
Lothian's Vino driver works with three generations of DL3 docks without vendor software.
Patent claims escalation
Synaptics demanded $25,000 compensation per week for patent infringement if Lothian didn't comply.
“monetary compensation from you in the amount of US$25,000 to recoup the costs and effort required to create the attached documentation of your infringing acts”
OIN referral
OIN referred Lothian to a UK lawyer but he took down his GitHub repository to comply with Synaptics.
Current status
Lothian stopped Vino driver work on Linux but may continue with non-patented components.
“Vino itself has to remain local until this is sorted out, I just can't afford to defend myself against Synaptics”
Synaptics' position
Synaptics claims DisplayLink is not an OIN member and its technology can't be licensed through OIN.
“DisplayLink is not a member of OIN, and none of its technology is licensable through OIN or any other organization”
Patent claims impact
Synaptics' patent claims stopped work on improving DisplayLink dock compatibility with Linux.
LLM assistance
Lothian used LLM to help develop Vino driver but faced patent claims from Synaptics.
DisplayLink technology
DisplayLink uses proprietary DL3 technology to compress video, audio and USB channels over USB 3.
Vino driver progress
Lothian's Vino driver could control three generations of DL3 docks without vendor software.
Patent claims resolution
Lothian stopped Vino driver work on Linux but may continue with non-patented components.
The one thing
Synaptics issued patent claims that stopped a Linux driver developer from improving DisplayLink dock compatibility.
