When booting 2.6.39.3 with radeon and KMS enabled the boot messages stop at some point (clocksource switching to TSC or something) and about 60 seconds later the screen turns into a noise pattern with some irregularities on top (i.e. crash).
This happens when the radeon driver is built-in.
This can be triggered too when it is a module by "insmod radeon.ko" when there is no provision to automatically load firmware (e.g via /sbin/hotplug). The insmod hangs for `cat /sys/class/firmware/timeout` seconds (default 60) and after that it crashes with identical symptoms. When /sbin/hotplug is present for loading firmware (radeon/RV620_pfp.bin, radeon/RV620_me.bin, radeon/R600_rlc.bin in this case) then all goes well.
Because of this it is not possible to use a built-in radeon driver with KMS enabled.
lspci -vv:
01:00.0 VGA compatible controller: ATI Technologies Inc RV620 LE [Radeon HD 3450] (prog-if 00 [VGA controller]) Subsystem: Dell Device 0342 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 16 Region 0: Memory at e0000000 (64-bit, prefetchable) [size=256M] Region 2: Memory at f7df0000 (64-bit, non-prefetchable) [size=64K] Region 4: I/O ports at dc00 [size=256] Expansion ROM at f7e00000 [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) Legacy Endpoint, MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <4us, L1 unlimited ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset- 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- LnkCap: Port #0, Speed 2.5GT/s, Width x16, ASPM L0s L1, Latency L0 <64ns, L1 <1us ClockPM- Surprise- LLActRep- BwNot- LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s, Width x16, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Not Supported, TimeoutDis- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis-, Selectable De-emphasis: -6dB Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -6dB Capabilities: [a0] MSI: Enable- Count=1/1 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Capabilities: [100 v1] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?> Kernel driver in use: radeon