Hi all, We are migrating a SCSI HBA driver from KEXT to DriverKit (DEXT), with our DEXT inheriting from IOUserSCSIParallelInterfaceController. We've encountered a data corruption issue that is reliably reproducible under specific conditions and are hoping for some assistance from the community. Hardware and Driver Configuration: Controller: LSI 3108 DEXT Configuration: We are reporting our hardware limitations to the framework via the UserReportHBAConstraints function, with the following key settings: // UserReportHBAConstraints... addConstraint(kIOMaximumSegmentAddressableBitCountKey, 0x20); // 32-bit addConstraint(kIOMaximumSegmentCountWriteKey, 129); addConstraint(kIOMaximumByteCountWriteKey, 0x80000); // 512KB Observed Behavior: Direct I/O vs. Buffered I/O We've observed that the I/O behavior differs drastically depending on whether it goes through the system file cache: 1. Direct I/O (Bypassing System Cache) -> 100% Successful When we use fio with the direct=1 flag, our read/write and data verification tests pass perfectly for all file sizes, including 20GB+. 2. Buffered I/O (Using System Cache) -> 100% Failure at >128MB Whether we use the standard cp command or fio with the direct=1 option removed to simulate buffered I/O, we observe the exact same, clear failure threshold: Test Results: File sizes ≤ 128MB: Success. Data checksums match perfectly. File sizes ≥ 256MB: Failure. Checksums do not match, and the destination file is corrupted. Evidence of failure reproduced with fio (buffered_integrity_test.fio, with direct=1 removed): fio --size=128M buffered_integrity_test.fio -> Test Succeeded (err=0). fio --size=256M buffered_integrity_test.fio -> Test Failed (err=92), reporting the following error, which proves a data mismatch during the verification phase: verify: bad header ... at file ... offset 1048576, length 1048576 fio: ... error=Illegal byte sequence Our Analysis and Hypothesis The phenomenon of "Direct I/O succeeding while Buffered I/O fails" suggests the problem may be related to the cache synchronization mechanism at the end of the I/O process: Our UserProcessParallelTask_Impl function correctly handles READ and WRITE commands. When cp or fio (buffered) runs, the WRITE commands are successfully written to the LSI 3108 controller's onboard DRAM cache, and success is reported up the stack. At the end of the operation, to ensure data is flushed to disk, the macOS file system issues an fsync, which is ultimately translated into a SYNCHRONIZE CACHE SCSI command (Opcode 0x35 or 0x91) and sent to our UserProcessParallelTask_Impl. We hypothesize that our code may not be correctly identifying or handling this SYNCHRONIZE CACHE opcode. It might be reporting "success" up the stack without actually commanding the hardware to flush its cache to the physical disk. The OS receives this "success" status and assumes the operation is safely complete. In reality, however, the last batch of data remains only in the controller's volatile DRAM cache and is eventually lost. This results in an incomplete or incorrect file tail, and while the file size may be correct, the data checksum will inevitably fail. Summary Our DEXT driver performs correctly when handling Direct I/O but consistently fails with data corruption when handling Buffered I/O for files larger than 128MB. We can reliably reproduce this issue using fio with the direct=1 option removed. The root cause is very likely the improper handling of the SYNCHRONIZE CACHE command within our UserProcessParallelTask. P.S. This issue did not exist in the original KEXT version of the driver. We would appreciate any advice or guidance on this issue. Thank you.

I created a custom class that inherits from IOUserSCSIPeripheralDeviceType00 in the DriverKit SCSIPeripheralsDriverKit framework. When I attempted to send a vendor-specific command to a USB storage device using the UserSendCDB function of this class instance, the function returned the error: kIOReturnNotPrivileged (iokit_common_err(0x2c1)) // privilege violation However, when using UserSendCDB in the same way to issue standard SCSI commands such as INQUIRY or Test Unit Ready, no error occurred and the returned sense data was valid. Why is UserSendCDB able to send standard SCSI commands successfully, but vendor-specific commands return kIOReturnNotPrivileged? Is there any required entitlement, DriverKit capability, or implementation detail needed to allow vendor-specific CDBs? Below are the entitlements of my DriverKit extension: <dict> <key>com.apple.developer.driverkit.transport.usb</key> <array> <dict> <key>idVendor</key> <integer>[number of vendorid]</integer> </dict> </array> <key>com.apple.developer.driverkit</key> <true/> <key>com.apple.developer.driverkit.allow-any-userclient-access</key> <true/> <key>com.apple.developer.driverkit.allow-third-party-userclients</key> <true/> <key>com.apple.developer.driverkit.communicates-with-drivers</key> <true/> <key>com.apple.developer.driverkit.family.scsicontroller</key> <true/> </dict> If there is any additional configuration or requirement to enable vendor-specific SCSI commands, I would appreciate your guidance. Environment: macOS15.6 M2 MacBook Pro

Hi! Following this ticket: https://developer.apple.com/forums/thread/808764?page=1#868010022 Is there any way to use the hardware RFID reading capabilities of an iPhone to read ISO15693 RF tags silently, and without a UI pop-up? Perhaps using other native iOS libraries than the NFC library? If not, is there a way for a business to request this feature be allowed in internally used apps only?

Have a 2019 Ford Edge w/ Sync 3.4, wired carplay. Worked fine w/ iPhone 16 Pro on iOS 18. Upgraded to iPhone 17 Pro, came w/ iOS 26, carplay hasn't worked since. I've kept trying throughout new iOS 26 releases, lately with iOS 26.3 Public Beta 1, still not working. Have a long running issue with updates and system diagnostics as I've tried over the last few months: FB20739050 There is also a Apple support community thread with issues like this (and a ton of others) - my first post there was https://discussions.apple.com/thread/256138283?answerId=261613103022&sortBy=oldest_first#261613103022 I'm hoping here in the developer forums someone can maybe take a look at the feedback item and various system diagnostics to pin-point the issue. I'm a little concerned it's still not fixed this far into the follow-up point releases of iOS 26. Appreciate any help, thanks! --Chuck

Why hasn't the watchOS app updated immediately after the iPhone app was updated? It remains stuck in "Installing" status on the Apple Watch.

Hello! I have app (macos and iPadOS platforms) with empbedded DEXT. The DEXT executable runs fine on both platforms (ver 26.2). Trying to execute from iPad App code: let sysExtWs = OSSystemExtensionsWorkspace.shared let sysExts = try sysExtWs.systemExtensions(forApplicationWithBundleID: appBudleId) but always getting OSSystemExtensionError.Code.missingEntitlement error. Which entitlement am I missing? Thank You!

I am developing a macOS virtual audio device using an Audio Server Plug-In (HAL). I want the virtual device to be visible to all applications only when my main app is running, and completely hidden from all apps when the app is closed. The goal is to dynamically control device visibility based on app state without reinstalling the driver.What is the recommended way for the app to notify the HAL plug-in about its running or closed state ? Any guidance on best-practice architecture for this scenario would be appreciated.

Hello! We develop a SAS driver and a service application for DAS devices. When users in our application create a RAID array on the device: On the 1st step, our dext driver mounts a new volume. At this step DiskUtil automatically tries to mount it. As there is no file system on the new volume - the MacOS system popup appears "The disk you attached was not readable by the computer" On the 2nd step our application creates the file system on this new volume. So we do not need this MacOS system popup to appear (as it may frustrate our users). We found a way to disable the global auto mount but this solution also impacts on other devices (which is not good). Are there any other possibilities to prevent the popup "The disk you attached was not readable by the computer" from appearing?

1. 环境描述 (Environment) OS: macOS 26.2 Hardware: Apple Silicon (M1/M2/M3) DriverKit SDK: DriverKit 19.0 / 20.0 Arch: Universal (x86_64, arm64, arm64e) SIP Status: Enabled (Works perfectly when Disabled) 2. 问题现象 (Problem Description) 在开启 SIP 的环境下，USB 驱动扩展（Dext）能安装，但插入设备时无法连接设备（驱动的Start方法未被调用）。 驱动状态： MacBook-Pro ~ % systemextensionsctl list 1 extension(s) --- com.apple.system_extension.driver_extension (Go to 'System Settings > General > Login Items & Extensions > Driver Extensions' to modify these system extension(s)) enabled active teamID bundleID (version) name [state] * * JK9U78YRLU com.ronganchina.usbapp.MyUserUSBInterfaceDriver (1.3/4) com.ronganchina.usbapp.MyUserUSBInterfaceDriver [activated enabled] 关键日志证据 (Key Logs) KernelManagerd: Error Domain=NSPOSIXErrorDomain Code=8 "Exec format error" Syspolicyd: failed to fetch ... /_CodeSignature/CodeRequirements-1 error=-10 AppleSystemPolicy: ASP: Security policy would not allow process DriverKit Kernel: DK: MyUserUSBInterfaceDriver user server timeout dext的 embedded.provisionprofile 已包含： com.apple.developer.driverkit com.apple.developer.driverkit.transport.usb (idVendor: 11977)

Note: This document is specifically focused on what happens after a DEXT has passed its initial code-signing checks. Code-signing issues are dealt with in other posts. Preliminary Guidance: Using and understanding DriverKit basically requires understanding IOKit, something which isn't entirely clear in our documentation. The good news here is that IOKit actually does have fairly good "foundational" documentation in the documentation archive. Here are a few of the documents I'd take a look at: IOKit Fundamentals IOKit Device Driver Design Guidelines Accessing Hardware From Applications Special mention to QA1075: "Making sense of IOKit error codes",, which I happened to notice today and which documents the IOReturn error format (which is a bit weird on first review). Those documents do not cover the full DEXT loading process, but they are the foundation of how all of this actually works. Understanding the IOKitPersonalities Dictionary The first thing to understand here is that the "IOKitPersonalities" is called that because it is in fact a fully valid "IOKitPersonalities" dictionary. That is, what the system actually uses that dictionary "for" is: Perform a standard IOKit match and load cycle in the kernel. The final driver in the kernel then uses the DEXT-specific data to launch and run your DEXT process outside the kernel. So, working through the critical keys in that dictionary: "IOProviderClass"-> This is the in-kernel class that your in-kernel driver loads "on top" of. The IOKit documentation and naming convention uses the term "Nub", but the naming convention is not consistent enough that it applies to all cases. "IOClass"-> This is the in-kernel class that your driver loads on top of. This is where things can become a bit confused, as some families work by: Routing all activity through the provider reference so that the DEXT-specific class does not matter (PCIDriverKit). Having the DEXT subclass a specific subclass which corresponds to a specific kernel driver (SCSIPeripheralsDriverKit). This distinction is described in the documentation, but it's easy to overlook if you don't understand what's going on. However, compare PCIDriverKit: "When the system loads your custom PCI driver, it passes an IOPCIDevice object as the provider to your driver. Use that object to read and write the configuration and memory of your PCI hardware." Versus SCSIPeripheralsDriverKit: Develop your driver by subclassing IOUserSCSIPeripheralDeviceType00 or IOUserSCSIPeripheralDeviceType05, depending on whether your device works with SCSI Block Commands (SBC) or SCSI Multimedia Commands (SMC), respectively. In your subclass, override all methods the framework declares as pure virtual. The reason these differences exist actually comes from the relationship and interactions between the DEXT families. Case in point, PCIDriverKit doesn't require a specific subclass because it wants SCSIControllerDriverKit DEXTs to be able to directly load "above" it. Note that the common mistake many developers make is leaving "IOUserService" in place when they should have specified a family-specific subclass (case 2 above). This is an undocumented implementation detail, but if there is a mismatch between your DEXT driver ("IOUserSCSIPeripheralDeviceType00") and your kernel driver ("IOUserService"), you end up trying to call unimplemented kernel methods. When a method is "missing" like that, the codegen system ends up handling that by returning kIOReturnUnsupported. One special case here is the "IOUserResources" provider. This class is the DEXT equivalent of "IOResources" in the kernel. In both cases, these classes exist as an attachment point for objects which don't otherwise have a provider. It's specifically used by the sample "Communicating between a DriverKit extension and a client app" to allow that sample to load on all hardware but is not something the vast majority of DEXT will use. Following on from that point, most DEXT should NOT include "IOMatchCategory". Quoting IOKit fundamentals: "Important: Any driver that declares IOResources as the value of its IOProviderClass key must also include in its personality the IOMatchCategory key and a private match category value. This prevents the driver from matching exclusively on the IOResources nub and thereby preventing other drivers from matching on it. It also prevents the driver from having to compete with all other drivers that need to match on IOResources. The value of the IOMatchCategory property should be identical to the value of the driver's IOClass property, which is the driver’s class name in reverse-DNS notation with underbars instead of dots, such as com_MyCompany_driver_MyDriver." The critical point here is that including IOMatchCategory does this: "This prevents the driver from matching exclusively on the IOResources nub and thereby preventing other drivers from matching on it." The problem here is that this is actually the exceptional case. For a typical DEXT, including IOMatchCategory means that a system driver will load "beside" their DEXT, then open the provider blocking DEXT access and breaking the DEXT. DEXT Launching The key point here is that the entire process above is the standard IOKit loading process used by all KEXT. Once that process finishes, what actually happens next is the DEXT-specific part of this process: IOUserServerName-> This key is the bundle ID of your DEXT, which the system uses to find your DEXT target. IOUserClass-> This is the name of the class the system instantiates after launching your DEXT. Note that this directly mimics how IOKit loading works. Keep in mind that the second, DEXT-specific, half of this process is the first point your actual code becomes relevant. Any issue before that point will ONLY be visible through kernel logging or possibly the IORegistry. __ Kevin Elliott DTS Engineer, CoreOS/Hardware

MacOS(Apple Silicon) IOKit driver for FPGA DMA transmission, kernel panic. Hardware and software configuration: MAC mini M1 2020 16GB, macOS Ventura 13.0 or 13.7.8 FPGA device capability: 64-bit Complete description: We've developed a DMA driver for PCIe devices (FPGA) based on IOKit. The driver can start normally through kextload, and the bar mapping, DMA registers, etc. are all correct. I am testing DMA data transmission, but a kernel panic has occurred. The specific content of the panic is as follows: {"bug_type":"210","timestamp":"2026-01-28 14:35:30.00 +0800","os_version":"macOS 13.0 (22A380)","roots_installed":0,"incident_id":"61C9B820-8D1B-4E75-A4EB-10DC2558FA75"} { "build" : "macOS 13.0 (22A380)", "product" : "Macmini9,1", "socId" : "0x00008103", "kernel" : "Darwin Kernel Version 22.1.0: Sun Oct 9 20:14:30 PDT 2022; root:xnu-8792.41.9~2/RELEASE_ARM64_T8103", "incident" : "61C9B820-8D1B-4E75-A4EB-10DC2558FA75", "crashReporterKey" : "6435F6BD-4138-412A-5142-83DD7E5B4F61", "date" : "2026-01-28 14:35:30.16 +0800", "panicString" : "panic(cpu 0 caller 0xfffffe0026c78c2c): "apciec[pcic0-bridge]::handleInterrupt: Request address is greater than 32 bits linksts=0x99000001 pcielint=0x02220060 linkcdmsts=0x00000000 (ltssm 0x11=L0)\n" @AppleT8103PCIeCPort.cpp:1301\nDebugger message: panic\nMemory ID: 0x6\nOS release type: User\nOS version: 22A380\nKernel version: Darwin Kernel Version 22.1.0: Sun Oct 9 20:14:30 PDT 2022; root:xnu-8792.41.9~2/RELEASE_ARM64_T8103\nFileset Kernelcache UUID: C222B4132B9708E5E0E2E8B8C5896410\nKernel UUID: 0BFE6A5D-118B-3889-AE2B-D34A0117A062\nBoot session UUID: 61C9B820-8D1B-4E75-A4EB-10DC2558FA75\niBoot version: iBoot-8419.41.10\nsecure boot?: YES\nroots installed: 0\nPaniclog version: 14\nKernelCache slide: 0x000000001d1b4000\nKernelCache base: 0xfffffe00241b8000\nKernel slide: 0x000000001e3f8000\nKernel text base: 0xfffffe00253fc000\nKernel text exec slide: 0x000000001e4e0000\nKernel text exec base: 0xfffffe00254e4000\nmach_absolute_time: 0x907c3082\nEpoch Time: sec usec\n Boot : 0x6979adbb 0x00023a6a\n Sleep : 0x00000000 0x00000000\n Wake : 0x00000000 0x00000000\n Calendar: 0x6979ae1a 0x00064953\n\nZone info:\n Zone map: 0xfffffe1000834000 - 0xfffffe3000834000\n . VM : 0xfffffe1000834000 - 0xfffffe14cd500000\n . RO : 0xfffffe14cd500000 - 0xfffffe1666e98000\n . GEN0 : 0xfffffe1666e98000 - 0xfffffe1b33b64000\n . GEN1 : 0xfffffe1b33b64000 - 0xfffffe2000830000\n . GEN2 : 0xfffffe2000830000 - 0xfffffe24cd4fc000\n . GEN3 : 0xfffffe24cd4fc000 - 0xfffffe299a1c8000\n . DATA : 0xfffffe299a1c8000 - 0xfffffe3000834000\n Metadata: 0xfffffe3f4d1ac000 - 0xfffffe3f551ac000\n Bitmaps : 0xfffffe3f551ac000 - 0xfffffe3f5ac94000\n\nCORE 0 recently retired instr at 0xfffffe002569d7a0\nCORE 1 recently retired instr at 0xfffffe002569eea0\nCORE 2 recently retired instr at 0xfffffe002569eea0\nCORE 3 recently retired instr at 0xfffffe002569eea0\nCORE 4 recently retired instr at 0xfffffe002569eea0\nCORE 5 recently retired instr at 0xfffffe002569eea0\nCORE 6 recently retired instr at 0xfffffe002569eea0\nCORE 7 recently retired instr at 0xfffffe002569eea0\nTPIDRx_ELy = {1: 0xfffffe2000c23010 0: 0x0000000000000000 0ro: 0x0000000000000000 }\nCORE 0 PVH locks held: None\nCORE 1 PVH locks held: None\nCORE 2 PVH locks held: None\nCORE 3 PVH locks held: None\nCORE 4 PVH locks held: None\nCORE 5 PVH locks held: None\nCORE 6 PVH locks held: None\nCORE 7 PVH locks held: None\nCORE 0 is the one that panicked. Check the full backtrace for details.\nCORE 1: PC=0xfffffe00279db94c, LR=0xfffffe00260d5d9c, FP=0xfffffe8ffecaf850\nCORE 2: PC=0xfffffe0025be76b0, LR=0xfffffe0025be7628, FP=0xfffffe8fff08f5f0\nCORE 3: PC=0x00000001c7cacd78, LR=0x00000001c7cacd84, FP=0x000000016f485130\nCORE 4: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8ffe1dff00\nCORE 5: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8fff5eff00\nCORE 6: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8ffed8bf00\nCORE 7: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8fff11bf00\nCompressor Info: 0% of compressed pages limit (OK) and 0% of segments limit (OK) with 0 swapfiles and OK swap space\nPanicked task 0xfffffe1b33aad678: 0 pages, 470 threads: pid 0: kernel_task\nPanicked thread: 0xfffffe2000c23010, backtrace: 0xfffffe8fff6eb6a0, tid: 265\n\t\t ... Kernel Extensions in backtrace:\n com.apple.driver.AppleT8103PCIeC(1.0)[A595D104-026A-39E5-93AA-4C87CE8C14D2]@0xfffffe0026c619d0->0xfffffe0026c86c97\n dependency: com.apple.driver.AppleARMPlatform(1.0.2)[11A9713E-6739-3A4C-8571-2D8EAA062278]@0xfffffe0025f13ff0->0xfffffe0025f6255f\n dependency: com.apple.driver.AppleEmbeddedPCIE(1)[E71CBCCD-AEB8-3E7B-933D-4FED4241BF13]@0xfffffe002654e0b0->0xfffffe00265684c7\n dependency: com.apple.driver.ApplePIODMA(1)[A419BABC-A7A3-316D-A150-7C2C2D1F6D53]@0xfffffe00269a24b0->0xfffffe00269a6c3b\n dependency: com.apple.driver.IODARTFamily(1)[03997E20-8A3F-3412-A4E8-BD968A75A07D]@0xfffffe00275bcf50->0xfffffe00275d0a3f\n dependency: com.apple.iokit.IOPCIFamily(2.9)[EC78F47B-530B-3F87-854E-0A0A5FD9BBB2]@0xfffffe0027934350->0xfffffe002795f3d3\n dependency: com.apple.iokit.IOReportFamily(47)[843B39D3-146E-3992-B7C7-960148685DC8]@0xfffffe0027963010->0xfffffe0027965ffb\n dependency: com.apple.iokit.IOThunderboltFamily(9.3.3)[B22BC005-BB7B-32A3-99C0-39F3BDBD8E54]@0xfffffe0027a5e3f0->0xfffffe0027b9a1a3\n\nlast started kext at 1915345919: com.sobb.pcie-dma\t1.0.0d1 (addr 0xfffffe00240e47f0, size 9580)\nlast stopped kext at 1774866338: com.sobb.pcie-dma\t1.0.0d1 (addr 0xfffffe00240e47f0, size 9580)\nloaded It seems that the DMA request address initiated by FPGA exceeded 32 bits, which was intercepted by PCIe root port and resulted in a kernel panic.This is also the case on macOS (M2). I have tried the following code interface: IOBufferMemoryDescriptor： a. withCapacity(bufferSize, kIODirectionInOut, true)； b. inTaskWithPhysicalMask(kernel_task, kIODirectionInOut, bufferSize, 0x00000000FFFFFFFFULL)。 The physical addresses of the constructed descriptors are all >32 bits; IODMACommand： a. withSpecification(kIODMACommandOutputHost64, 64, 0, IODMACommand::kMapped, 0, 0)，gen64IOVMSegments() The allocated IOVM address must be>32 bits, which will generate a kernel panic when used later. b.withSpecification(kIODMACommandOutputHost32, 32, 0, IODMACommand::kMapped, 0, 0)，gen32IOVMSegments() The allocation of IOVM failed with error code kIOReturnenMessageTooLarge. So after the above attempts, the analysis shows that the strategy of Dart+PCIe root port on macOS (Apple Silicon) is causing the failure of 64 bit DMA address transfer. I have two questions: a. Does Dart in macOS (Apple Silicon) definitely not allocate <=32-bit IOVM addresses? b. Is there any other way to achieve DMA transfer for FGPA devices on macOS (Apple Silicon)? Thanks！

Dear Support Team, ​I am writing to seek technical assistance regarding a persistent issue with Dolby Vision exporting in DaVinci Resolve 20 on my iPad Pro 12.9-inch (2021, M1 chip) running iPadOS 26.0.1. ​The Issue: Despite correctly configuring the project for a Dolby Vision workflow and successfully completing the dynamic metadata analysis, the "Dolby Vision Profile" dropdown menu (and related embedding options) is completely missing from the Advanced Settings in the Deliver page. ​My Current Configuration & Steps Taken: ​Software Version: DaVinci Resolve Studio 20 (Studio features like Dolby Vision analysis are active and functional). ​Project Settings: Color Science: DaVinci YRGB Color Managed. ​Dolby Vision: Enabled (Version 4.0) with Mastering Display set to 1000 nits. ​Output Color Space: Rec.2100 ST2084. ​Color Page: Dynamic metadata analysis has been performed, and "Trim" controls are functional. ​Export Settings: ​Format: QuickTime / MP4. ​Codec: H.265 (HEVC). ​Encoding Profile: Main 10. ​The Problem: Under "Advanced Settings," there is no option to select a Dolby Vision Profile (e.g., Profile 8.4) or to "Embed Dolby Vision Metadata." ​Potential Variables: ​System Version: I am currently running iPadOS 26. ​Apple ID: My iPad is currently not logged into an Apple ID. I suspect this might be preventing the app from accessing certain system-level AVFoundation frameworks or Dolby DRM/licensing certificates required for metadata embedding. ​Could you please clarify if the "Dolby Vision Profile" option is dependent on a signed-in Apple ID for hardware-level encoding authorization, or if this is a known compatibility issue with the current iPadOS 26 build? ​I look forward to your guidance on how to resolve this. ​Best regards, INSOFT_Fred