Error val about ultra 200s VT-D ECAP_REG

hujiaodigua · ‎12-05-2024

I bought a ultra 7 265k processor to learn how to configure iommu scalable mode.

However, there are some different between the real soc with datasheet.

real boot log shows the ecap val is 0x1aca9a00f0ef5e(for gpu) and 0x1aca9a00f0efde(for device)

VTDPVC0BAR Registers shows 0x1aca9a04f0efde(for device)

Extended Capability Register (ECAP_REG_0_0_0_VTDBAR)

package

001ACA9A04F0EFDEh

It is obvious that this is not the same.

datasheet-vol-1 notes Nested - default Intel ® VT-d engine support Nested translation

Although, NEST field is valid only when PASID field is reported as Set. The error information about nested translation is highly deceptive.

40

0h

RO/V

Process Address Space ID Support (PASID)

0: Hardware does not support requests tagged with Process Address Space IDs.
1: Hardware supports requests tagged with Process Address Space IDs.

26

1h

RO/V

Nested Translation Support (NEST)

0: Hardware does not support nested translations.
1: Hardware supports nested translations.
This field is valid only when PASID field is reported as Set.

DhannielM_Intel · ‎12-18-2024

Hi hujiaodigua,

Thanks for posting in the community, to further assist you on this matter first can you send me your system information? Please download the Intel System Support Utility (SSU), this will generate a text file that compiles all your system information. You can follow this link for instructions and send the text file here: Help Guide for the Intel® System Support Utility.

Additionally, can you tell me if you are using Linux or Windows? If Linux can you specify if what vendor you are using and the current version of the OS?

Best regards,

Dhanniel M.

Intel Customer Support Technician

hujiaodigua · ‎12-22-2024

Thanks Dhanniel,

I used Ubuntu-20.04 with linux-kernel-6.12.1

Attached file cannot upload, so scan results as flow:

# SSU Scan Information
Scan Info:
     Version:"1.0.0.0"
     Scan Date:"2024/12/23"
     Scan Time:"01:13:24"

## Scanned Hardware
Computer:
          BaseBoard Manufacturer:"Gigabyte Technology Co., Ltd."
          Bios Mode:"UEFI"
          Bios Version/Date:"F10d,10/30/2024"
          CD or DVD:"Not Available"
          Platform Role:"Linux sw-MS-7D25 6.12.1-iommudebugfs #3 SMP PREEMPT_DYNAMIC Mon Nov 25 01:39:55 CST 2024 x86_64 x86_64 x86_64 GNU/Linux"
          Processor:"Intel(R) Core(TM) Ultra 7 265K"
          Serial Number:"Default string"
          SMBIOS Version:"3.7.0"
          Sound Cards:"HDA-Intel - HDA Intel PCH"
          Sound Cards:"HDA Intel PCH at 0x4000210000 irq 235"
          System Manufacturer:"Gigabyte Technology Co., Ltd."
          System Model:"Z890M AORUS ELITE WIFI7 ICE"
          System Type:"x64-based PC"
          - Display
               - "Intel Corporation Device 7d67 (rev 06) (prog-if 00 [VGA controller])"
                    Adapter RAM:"size=16M"
                    Adapter RAM:"size=256M"
                    Capabilities:"[40] Vendor Specific Information: Len=0c <?>"
                    Capabilities:"[70] Express Root Complex Integrated Endpoint, MSI 00"
                    Capabilities:"[ac] MSI: Enable+ Count=1/1 Maskable+ 64bit+"
                    Capabilities:"[d0] Power Management version 3"
                    Capabilities:"[100] Null"
                    Capabilities:"[110] Process Address Space ID (PASID)"
                    Capabilities:"[200] Address Translation Service (ATS)"
                    Capabilities:"[420] Resizable BAR <?>"
                    Capabilities:"[320] Single Root I/O Virtualization (SR-IOV)"
                    Capabilities:"[400] Latency Tolerance Reporting"
                    Caption:"Intel Corporation Device 7d67 (rev 06) (prog-if 00 [VGA controller])"
                    Device ID:"1458:d000"
                    Driver:"i915"
                    Driver Path:"/lib/modules/6.12.1-iommudebugfs/kernel/drivers/gpu/drm/i915/i915.ko"
                    Driver Provider:"Intel Corporation"
                    Driver Provider:"Tungsten Graphics, Inc."
                    Driver Version:""
                    Flags:"bus master, fast devsel, latency 0, IRQ 233"
                    I/O Ports:"Not Available"
                    Location:"pci@0000:00:02.0"
                    Manufacturer:"Intel Corporation [8086]"
                    Power Management Capabilities:"Power Management version 3"
                    Refresh Rate - Current:"59.95"
                    Resolution:"2560x1440"
          - Memory
               Physical Memory (Available):"44837 MB"
               Physical Memory (Installed):"47564 MB"
               Physical Memory (Total):"49612 MB"
               - "Controller0-ChannelA-DIMM1"
                    Capacity:"24576 MB"
                    Configured Clock Speed:"Not Available"
                    Configured Voltage:"1.1 V"
                    Data Width:"64 bits"
                    Form Factor:"DIMM"
                    Interleave Position:"First Position"
                    Locator:"Controller0-ChannelA-DIMM1"
                    Manufacturer:"Shenzhen Zhongshi Technology Co Ltd"
                    Maximum Voltage:"1.1 V"
                    Minimum Voltage:"1.0 V"
                    Part Number:""
                    Serial Number:"13000000"
                    Speed:"Not Available"
                    Type:"Synchronous"
               - "Controller0-ChannelB-DIMM1"
                    Capacity:"24576 MB"
                    Configured Clock Speed:"Not Available"
                    Configured Voltage:"1.1 V"
                    Data Width:"64 bits"
                    Form Factor:"DIMM"
                    Interleave Position:"First Position"
                    Locator:"Controller0-ChannelB-DIMM1"
                    Manufacturer:"Shenzhen Zhongshi Technology Co Ltd"
                    Maximum Voltage:"1.1 V"
                    Minimum Voltage:"1.0 V"
                    Part Number:""
                    Serial Number:"14000000"
                    Speed:"Not Available"
                    Type:"Synchronous"
          - Motherboard
               Manufacturer:"Gigabyte Technology Co., Ltd."
               Product:"Z890M AORUS ELITE WIFI7 ICE"
               Serial Number:"Default string"
               Version:"x.x"
          - Networking
               - "Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection (rev 01)"
                    Supports auto-negotiation:"No"
                    Advertised auto-negotiation:"No"
                    Auto-negotiation:"off"
                    Availability:"enp2s0f0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500"
                    Capabilities:"[40] Power Management version 3"
                    Capabilities:"[50] MSI: Enable- Count=1/1 Maskable+ 64bit+"
                    Capabilities:"[70] MSI-X: Enable+ Count=64 Masked-"
                    Capabilities:"[a0] Express Endpoint, MSI 00"
                    Capabilities:"[e0] Vital Product Data"
                    Capabilities:"[100] Advanced Error Reporting"
                    Capabilities:"[140] Device Serial Number 00-e0-ec-ff-ff-26-12-72"
                    Capabilities:"[150] Alternative Routing-ID Interpretation (ARI)"
                    Capabilities:"[160] Single Root I/O Virtualization (SR-IOV)"
                    Caption:"Not Available"
                    Default IP Gateway:"192.168.8.1"
                    DHCP Enabled:"Yes"
                    DHCP Lease Expires:"Not Available"
                    DHCP Lease Obtained:"Not Available"
                    DHCP Server:"Not Available"
                    Driver:"ixgbe"
                    Driver Path:"/lib/modules/6.12.1-iommudebugfs/kernel/drivers/net/ethernet/intel/ixgbe/ixgbe.ko"
                    Driver Provider:""
                    Driver Version:""
                    Duplex:"Full"
                    Firmware Version:"0x800004e0, 1.307.0"
                    Interface:"enp2s0f0"
                    I/O Ports:"Not Available"
                    IP Address:"192.168.8.247"
                    IP Subnet:"255.255.255.0"
                    MAC Address:"00:e0:ec:26:12:72"
                    Location:"02:00.0"
                    Manufacturer:"Intel Corporation"
                    Net Connection ID:"Not Available"
                    Port:"Other"
                    Power Management:"Supports Wake-on: d"
                    Power Management:"Wake-on: d"
                    Speed:"10000Mb/s"
                    Supported link modes:"10000baseT/Full, Supported pause frame use: Symmetric"
                    Advertised link modes:"10000baseT/Full, Advertised pause frame use: Symmetric"
                    Partner advertised link modes:"Not Available"
               - "Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection (rev 01)"
                    Supports auto-negotiation:"No"
                    Advertised auto-negotiation:"No"
                    Auto-negotiation:"off"
                    Availability:"enp2s0f1: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500"
                    Capabilities:"[40] Power Management version 3"
                    Capabilities:"[50] MSI: Enable- Count=1/1 Maskable+ 64bit+"
                    Capabilities:"[70] MSI-X: Enable+ Count=64 Masked-"
                    Capabilities:"[a0] Express Endpoint, MSI 00"
                    Capabilities:"[e0] Vital Product Data"
                    Capabilities:"[100] Advanced Error Reporting"
                    Capabilities:"[140] Device Serial Number 00-e0-ec-ff-ff-26-12-72"
                    Capabilities:"[150] Alternative Routing-ID Interpretation (ARI)"
                    Capabilities:"[160] Single Root I/O Virtualization (SR-IOV)"
                    Caption:"Not Available"
                    Default IP Gateway:"Not Available"
                    DHCP Enabled:"Yes"
                    DHCP Lease Expires:"Not Available"
                    DHCP Lease Obtained:"Not Available"
                    DHCP Server:"Not Available"
                    Driver:"ixgbe"
                    Driver Path:"/lib/modules/6.12.1-iommudebugfs/kernel/drivers/net/ethernet/intel/ixgbe/ixgbe.ko"
                    Driver Provider:""
                    Driver Version:""
                    Duplex:"Unknown! (255)"
                    Firmware Version:"0x800004e0, 1.307.0"
                    Interface:"enp2s0f1"
                    I/O Ports:"Not Available"
                    IP Address:"Not Available"
                    IP Subnet:"Not Available"
                    MAC Address:"00:e0:ec:26:12:73"
                    Location:"02:00.1"
                    Manufacturer:"Intel Corporation"
                    Net Connection ID:"Not Available"
                    Port:"Other"
                    Power Management:"Supports Wake-on: d"
                    Power Management:"Wake-on: d"
                    Speed:"Unknown!"
                    Supported link modes:"10000baseT/Full, Supported pause frame use: Symmetric"
                    Advertised link modes:"10000baseT/Full, Advertised pause frame use: Symmetric"
                    Partner advertised link modes:"Not Available"
               - Interface virbr0
                    Supports auto-negotiation:"No"
                    Advertised auto-negotiation:"No"
                    Auto-negotiation:"off"
                    Availability:"virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500"
                    Capabilities:"Not Available"
                    Caption:"Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection (rev 01)"
                    Default IP Gateway:"Not Available"
                    DHCP Enabled:"Yes"
                    DHCP Lease Expires:"Not Available"
                    DHCP Lease Obtained:"Not Available"
                    DHCP Server:"Not Available"
                    Driver:"bridge"
                    Driver Path:"/lib/modules/6.12.1-iommudebugfs/kernel/net/bridge/bridge.ko"
                    Driver Provider:""
                    Driver Version:""
                    Duplex:"Unknown! (255)"
                    Firmware Version:"N/A"
                    Interface:"virbr0"
                    I/O Ports:"Not Available"
                    IP Address:"192.168.122.1"
                    IP Subnet:"255.255.255.0"
                    MAC Address:"52:54:00:c6:5f:13"
                    Location:"Not Available"
                    Manufacturer:"Not Available"
                    Net Connection ID:"Not Available"
                    Port:"Other"
                    Power Management:"Not Available"
                    Speed:"Unknown!"
                    Supported link modes:"Not reported, Supported pause frame use: No"
                    Advertised link modes:"Not reported, Advertised pause frame use: No"
                    Partner advertised link modes:"Not Available"
               - Interface virbr0-nic
                    Supports auto-negotiation:"No"
                    Advertised auto-negotiation:"No"
                    Auto-negotiation:"off"
                    Availability:"virbr0-nic: flags=4098<BROADCAST,MULTICAST>  mtu 1500"
                    Capabilities:"Not Available"
                    Caption:"Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection (rev 01)"
                    Default IP Gateway:"Not Available"
                    DHCP Enabled:"Yes"
                    DHCP Lease Expires:"Not Available"
                    DHCP Lease Obtained:"Not Available"
                    DHCP Server:"Not Available"
                    Driver:"tun"
                    Driver Path:"(builtin)"
                    Driver Provider:"name:           tun"
                    Driver Provider:"(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
                    Driver Version:""
                    Duplex:"Full"
                    Firmware Version:""
                    Interface:"virbr0-nic"
                    I/O Ports:"Not Available"
                    IP Address:"Not Available"
                    IP Subnet:"Not Available"
                    MAC Address:"52:54:00:c6:5f:13"
                    Location:"Not Available"
                    Manufacturer:"Not Available"
                    Net Connection ID:"Not Available"
                    Port:"Twisted Pair"
                    Power Management:"Not Available"
                    Speed:"10000Mb/s"
                    Supported link modes:"Not reported, Supported pause frame use: No"
                    Advertised link modes:"Not reported, Advertised pause frame use: No"
                    Partner advertised link modes:"Not Available"
               - "Realtek Semiconductor Co., Ltd. Device 8922 (rev 01)"
                    Auto-Negotiation:"Not Available"
                    Availability:"wlp129s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500"
                    Capabilities:"[40] Power Management version 3"
                    Capabilities:"[50] MSI: Enable+ Count=1/8 Maskable+ 64bit+"
                    Capabilities:"[70] Express Endpoint, MSI 00"
                    Capabilities:"[100] Advanced Error Reporting"
                    Capabilities:"[148] Device Serial Number 00-e0-4c-ff-fe-89-22-01"
                    Capabilities:"[158] Latency Tolerance Reporting"
                    Capabilities:"[160] L1 PM Substates"
                    Capabilities:"[170] Vendor Specific Information: ID=0002 Rev=4 Len=100 <?>"
                    Capabilities:"[270] Data Link Feature <?>"
                    Caption:"Not Available"
                    Default IP Gateway:"192.168.8.1"
                    DHCP Enabled:"Yes"
                    DHCP Lease Expires:"Not Available"
                    DHCP Lease Obtained:"Not Available"
                    DHCP Server:"Not Available"
                    Driver:"rtw89_8922ae"
                    Driver Path:"/lib/modules/6.12.1-iommudebugfs/kernel/drivers/net/wireless/realtek/rtw89/rtw89_8922ae.ko"
                    Driver Provider:"Realtek Corporation"
                    Driver Version:""
                    Duplex:"Not Available"
                    Firmware Version:"N/A"
                    Interface:"wlp129s0"
                    I/O Ports:"Not Available"
                    IP Address:"192.168.8.220"
                    IP Subnet:"255.255.255.0"
                    MAC Address:"e8:47:3a:e7:b0:8e"
                    Location:"81:00.0"
                    Manufacturer:"Realtek Semiconductor Co., Ltd."
                    Net Connection ID:"Not Available"
                    Port:"Not Available"
                    Power Management:"Not Available"
                    Speed:"Not Available"
                    Supported Link Modes:"Not Available"
                    Advertised link modes:"Not Available"
                    Partner advertised link modes:"Not Available"
          - Operating System
               Boot Device:"/dev/sda2"
               Last Reset:"up 17 min,  1 user,  load average: 0.63, 1.10, 0.88"
               Locale:"en_US"
               OS Manufacturer:"Ubuntu 20.04.6 LTS \n \l"
               OS Name:"Ubuntu 20.04.6 LTS \n \l"
               Page File:"/swapfile"
               Page File Space (Available):"2097148"
               Page File Space (Used):"0"
               Physical Memory (Available):"44856 MB"
               Physical Memory (Installed):"47564 MB"
               Physical Memory (Total):"49612 MB"
               Version:"6.12.1-iommudebugfs GNU/Linux"
               Virtual Memory (Available):"2097148"
               Virtual Memory (Total):"48706308"
          - Processor
               - "Intel(R) Core(TM) Ultra 7 265K"
                    Architecture:"x86_64"
                    Available:"Offline"
                    Byte Order:"Little Endian"
                    Cache Size:"30720 KB"
                    Caption:"Intel(R) Core(TM) Ultra 7 265K"
                    - Characteristics
                         64-bit capable
                         Enhanced Virtualization
                         Execute Protection
                         Multi-Core
                         Power/Performance Control
                    CPU Speed (Minimum):"1530.628"
                    CPU Speed (Maximum):"8500 MHz"
                    Current Voltage:"0.9 V"
                    External Clock:"100 MHz"
                    Family:"Not Available"
                    Flags:"Not Available"
                    ID:"62 06 0C 00 FF FB EB BF"
                    Level 1 Cache:"960 KiB
fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault ssbd ibrs ibpb stibp ibrs_enhanced tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid rdt_a rdseed adx smap clflushopt clwb intel_pt sha_ni xsaveopt xsavec xgetbv1 xsaves split_lock_detect avx_vnni lam wbnoinvd dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req hfi vnmi umip pku ospke waitpkg gfni vaes vpclmulqdq rdpid bus_lock_detect movdiri movdir64b fsrm md_clear serialize arch_lbr ibt flush_l1d arch_capabilities"
                    Level 2 Cache:"60 MiB"
                    Level 3 Cache:"30 MiB"
                    Load:"load average: 0.63, 1.10, 0.88"
                    Manufacturer:"Intel(R) Corporation"
                    Model:"198"
                    Name:"Intel(R) Core(TM) Ultra 7 265K"
                    Number of Cores:"20"
                    Number of Cores - Enabled:"20"
                    Part Number:"To Be Filled By O.E.M."
                    Socket Designation:"U3E1"
                    Status:"Populated, Enabled"
                    Version:"Intel(R) Core(TM) Ultra 7 265K"
                    Voltage:"0.9 V"
                    Virtualization:"Not Available"
          - Storage
               - "ST1000NX0423"
                    Capabilities:"LBA, IORDY(can be disabled)"
                    Capabilities:"Queue depth: 32"
                    Capabilities:"Standby timer values: spec'd by Standard, no device specific minimum"
                    Capabilities:"R/W multiple sector transfer: Max = 16	Current = 16"
                    Capabilities:"Recommended acoustic management value: 254, current value: 0"
                    Capabilities:"DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6 "
                    Capabilities:"Cycle time: min=120ns recommended=120ns"
                    Capabilities:"PIO: pio0 pio1 pio2 pio3 pio4 "
                    Capabilities:"Cycle time: no flow control=120ns  IORDY flow control=120ns"
                    Caption:"/dev/sda"
                    Cylinders - Total:"16383"
                    Description:"ATA device, with non-removable media"
                    Firmware:"NA03"
                    Heads - Total:"16"
                    Index:"Not Available"
                    Interface Type:"ATA"
                    Manufacturer:"ST1000NX0423"
                    Model:"ST1000NX0423"
                    Name:"sda"
                    Partitions:"Not Available"
                    Sectors - Per Track:"63"
                    Serial Number:"S470WMGK"
                    Size:"1024*1024: 953869 MBytes"
                    Size:"1000*1000: 1000204 MBytes (1000 GB)"
                    Size - Available:"Filesystem     1K-blocks      Used Available Use% Mounted on"
                    Size - Available:"/dev/sda2      959792644 171125376 739839068  19% /"
                    Size - Available:"/dev/sda1         523248      7168    516080   2% /boot/efi"
                    SMART Attributes:"* SMART Command Transport (SCT) feature set"
                    SMART Attributes:"* SMART error logging"
                    SMART Attributes:"* SMART feature set"
                    SMART Attributes:"* SMART self-test"
                    - SMART
                         001 Raw_Read_Error_Rate :082:"---"
                         003 Spin_Up_Time :095:"---"
                         004 Start_Stop_Count :100:"---"
                         005 Reallocated_Sector_Ct :100:"---"
                         007 Seek_Error_Rate :088:"---"
                         009 Power_On_Hours :073:"---"
                         010 Spin_Retry_Count :100:"---"
                         012 Power_Cycle_Count :100:"---"
                         184 End-to-End_Error :100:"---"
                         187 Reported_Uncorrect :100:"---"
                         188 Command_Timeout :100:"---"
                         189 High_Fly_Writes :100:"---"
                         190 Airflow_Temperature_Cel :066:"---"
                         191 G-Sense_Error_Rate :100:"---"
                         192 Power-Off_Retract_Count :100:"---"
                         193 Load_Cycle_Count :088:"---"
                         194 Temperature_Celsius :034:"---"
                         195 Hardware_ECC_Recovered :001:"---"
                         196 Reallocated_Event_Count :100:"---"
                         197 Current_Pending_Sector :100:"---"
                         198 Offline_Uncorrectable :100:"---"
                         199 UDMA_CRC_Error_Count :200:"---"
                         240 Head_Flying_Hours :100:"---"
                         241 Total_LBAs_Written :100:"---"
                         242 Total_LBAs_Read :100:"---"

DhannielM_Intel · ‎12-22-2024

Hi hujiaodigua,

Thanks for sharing the SSU logs. I want to make sure I have all the information correct. Could you confirm if you are using virtualization when running Linux, or is it directly installed on your SSD?

Best regards,

Dhanniel M.

Intel Customer Support Technician

hujiaodigua · ‎12-23-2024

Hi Dhanniel,

I installed Ubuntu OS on my SSD directly and booted Linux with cmdline "intel_iommu=on,sm_on".

The problem is simple:

The real value of VT-D Extended Capability Register NEST field is different from the datasheet.

DhannielM_Intel · ‎12-23-2024

Hi hujiaodigua,

Thanks for sharing this to me, allow me to further investigate this issue on my end to provide you better resolution.

Best regards,

Dhanniel M.

Intel Customer Support Technician

hujiaodigua · ‎12-23-2024

Thanks Dhanniel,

Maybe, updating the Intel Ultra 200s datasheet with the actual case is fine.

Merry Christmas and happy New Year!

DhannielM_Intel · ‎02-04-2025

Hello hujiaodigua,

After investigating this thorougly, it was found that the datasheet provides the default value of the fields before any settings applied. The real system shows the value that is applied to the register after reset, and it doesn’t have to be similar to default. Let me know if you have other clarification about this.

Best regards,

Dhanniel M.

Intel Customer Support Technician

DhannielM_Intel · ‎02-09-2025

Hello hujiaodigua,

I hope you had the opportunity to review the information I provided earlier. If you have any questions or need further clarification, please feel free to reach out.

Best regards,

Dhanniel M.

Intel Customer Support Technician

DhannielM_Intel · ‎02-12-2025

Hi hujiaodigua,

Since I haven't heard back from you, I will close this inquiry now. If you need further assistance, please submit a new question, as this thread will no longer be monitored.

Best regards,

Dhanniel M.

Intel Customer Support Technician

hujiaodigua · ‎02-17-2025

Hi Dhanniel,

Thanks for the response.

My account was locked throughout the past week.

The real system shows the value that is applied to the register after reset, and it doesn’t have to be similar to default. Let me know if you have other clarification about this.

It is really confusing.

The default value of a register typically refers to its initial value when the device is powered on or reset. This value should be specified in the datasheet of the component you're looking at. It can depend on the specific register and the type of device you're working with (e.g., microcontroller, FPGA, sensor, etc.).

Thanks.