Sorry, I've since upgraded my *entire* system from testing to unstable, and the problem went away at some point.
If it wasn't a bug in some dependency, my guess is that something had migrated to testing without all of its true dependencies having migrated. There are a lot of ways that that can happen - plugins, changes in the *use* of some already-existing library call (e.g. accepting new enum values). You can debootstrap from http://snapshot.debian.org/archive/debian/20161219T152404Z/ to investigate the underlying cause, since if it's a missing dependency problem, it *will* cause problems again sooner or later. But here's the information you requested, for what it's worth: 00:01.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Richland [Radeon HD 8610G] [1002:990f] (prog-if 00 [VGA controller]) Subsystem: Hewlett-Packard Company Richland [Radeon HD 8610G] [103c:216b] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 32 Region 0: Memory at e0000000 (32-bit, prefetchable) [size=256M] Region 1: I/O ports at 3000 [size=256] Region 2: Memory at f0300000 (32-bit, non-prefetchable) [size=256K] [virtual] Expansion ROM at 000c0000 [disabled] [size=128K] Capabilities: [50] Power Management version 3 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Capabilities: [58] Express (v2) Root Complex Integrated Endpoint, MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0 ExtTag+ RBE+ DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ MaxPayload 128 bytes, MaxReadReq 128 bytes DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend- DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-, OBFF Not Supported DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee0100c Data: 41a2 Capabilities: [100 v1] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?> Kernel driver in use: radeon Kernel modules: radeon
