On Wed, 16 Apr 2025 01:36:15 +0800 Tomita Moeko <tomitamo...@gmail.com> wrote: > > The generation register also exists on discrete GPUs. In the new xe > driver [1], the Battlemage discrete GPU shares the same logic reading > GMD_ID_DISPLAY register. The driver itself uses is_dgfx bit mapped to > device id. In QEMU, we need to know whether the device is a supported > IGD device first before applying the IGD-specific quirk, especially > for legacy mode. > > The most feasible way is to check if kernel exposes VFIO_REGION_SUBTYPE_ > INTEL_IGD_OPREGION on that device I think, as only IGD has OpRegion. > > i915 driver [2] and Arrow Lake datasheet [3] shows that Intel has > removed the BDSM register by making the DSM range part of BAR2 since > Meteor Lake and onwards. QEMU only need to quirk on the register for > IGD devices until Raptor Lake, meaning that the device list is fixed > for now. > > By the way, for legacy mode, I think we should only support it until > Gen 9, as Intel only provide VBIOS or CSM support until that generation, > and seabios cannot handle 64 bit BDSM register. I'm also wondering if > VGA really works on newer generations.
If it's a VGA class device, it really should, but without CSM I could see why you have doubts. > Maybe we can continue with current igd_gen, but implement a logic like: > if (!intel graphics) > return; > if (!has VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION) > return; > setup_opregion(); // make x-igd-opregion automatically enabled? > if (gen <= 9) > setup_legacy_mode(); > if (gen >= 6 && gen <=9) > setup_32bit_bdsm(): > else if (gen >= 9 && gen <= 12) > setup_64bit_bdsm(); > // ... > // optional quirks like lpc bridge id > > A table can also be used to precisely track all the gen 6-12 devices. This seems reasonable to me. > Attached a config space dump of Intel A770 discrete GPU for reference > > 03:00.0 VGA compatible controller: Intel Corporation DG2 [Arc A770] (rev 08) > (prog-if 00 [VGA controller]) > Subsystem: Intel Corporation Device 1020 > 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 ? routed to IRQ 181 > IOMMU group: 19 > Region 0: Memory at 81000000 (64-bit, non-prefetchable) [size=16M] > Region 2: Memory at 6000000000 (64-bit, prefetchable) [size=16G] > Expansion ROM at 82000000 [disabled] [size=2M] > Capabilities: [40] Vendor Specific Information: Len=0c <?> > Capabilities: [70] Express (v2) Endpoint, IntMsgNum 0 > DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <64ns, > L1 <1us > ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ > SlotPowerLimit 0W TEE-IO- > DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq- > RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ FLReset- > MaxPayload 128 bytes, MaxReadReq 128 bytes > DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq+ AuxPwr- > TransPend- > LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit > Latency L0s <64ns, L1 <1us Hmm, hardware bug? Surely the A770 is not a Gen1, x1 device. Something is going on with the interrupt pin above too. At least it claims FLReset+ above, does it work reliably though? Seems like there are various reports of Arc GPUs not working well with assignment due to reset issues. Thanks, Alex > ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+ > LnkCtl: ASPM Disabled; RCB 64 bytes, LnkDisable- CommClk- > ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- > LnkSta: Speed 2.5GT/s, Width x1 > TrErr- Train- SlotClk- DLActive- BWMgmt- ABWMgmt- > DevCap2: Completion Timeout: Range B, TimeoutDis+ NROPrPrP- LTR+ > 10BitTagComp+ 10BitTagReq+ OBFF Not Supported, ExtFmt+ > EETLPPrefix- > EmergencyPowerReduction Not Supported, > EmergencyPowerReductionInit- > FRS- TPHComp- ExtTPHComp- > AtomicOpsCap: 32bit- 64bit- 128bitCAS- > DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- > AtomicOpsCtl: ReqEn- > IDOReq- IDOCompl- LTR+ EmergencyPowerReductionReq- > 10BitTagReq- OBFF Disabled, EETLPPrefixBlk- > LnkCap2: Supported Link Speeds: 2.5GT/s, Crosslink- Retimer- > 2Retimers- DRS- > LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis- > Transmit Margin: Normal Operating Range, > EnterModifiedCompliance- ComplianceSOS- > Compliance Preset/De-emphasis: -6dB de-emphasis, 0dB > preshoot > LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete- > EqualizationPhase1- > EqualizationPhase2- EqualizationPhase3- > LinkEqualizationRequest- > Retimer- 2Retimers- CrosslinkRes: unsupported > Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable+ 64bit+ > Address: 00000000fee008b8 Data: 0000 > Masking: 00000000 Pending: 00000000 > Capabilities: [d0] 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: [100 v1] Alternative Routing-ID Interpretation (ARI) > ARICap: MFVC- ACS-, Next Function: 0 > ARICtl: MFVC- ACS-, Function Group: 0 > Capabilities: [420 v1] Physical Resizable BAR > BAR 2: current size: 16GB, supported: 256MB 512MB 1GB 2GB 4GB > 8GB 16GB > Capabilities: [400 v1] Latency Tolerance Reporting > Max snoop latency: 15728640ns > Max no snoop latency: 15728640ns > Kernel driver in use: i915 > Kernel modules: i915, xe
