Dear All, I am currently developing a high throughput audio system which operates via PCIe tunneled into a USB4 interface. This include a custom FPGA based hardware and custom Audio DriverKit driver. While performing read operation via the hw DMA (that is a Host to Device transfer), I am noticing sparse latency spikes into the read transfers. Specifically, 4KB operations (which I assume including MRd + CpID) take normally from 5us to 40us to be completed, perfectly fine for my case. However, in some rare occasions, they can end up to 400us, which causes me overruns. The measurements have been carried out from the FPGA and they include the overall request and transfer time. While trying to tackle the problem, I'm investigating the possible power saving options and performance constraint methods at my disposal. I currently use these methods to mitigate the problem. ChangePowerState(kIOServicePowerCapabilityOn); SetPowerOverride(true); RequireMaxBusStall(kIOMaxBusStall25usec); CreatePMAssertion(kIOServicePMAssertionCPUBit | kIOServicePMAssertionForceFullWakeupBit, &ivars->PMAssertionID, false); The buffers are currently about 16MB, single segment, 16KB aligned and, of course, "prepared" for DMA. The system run for 3 hours without any overrun, but I'm not still fully convinced about its reliability. May someone provide me some comments on this? Are there profiling tools that I can use? Feel free to request me any required detail. The testing system is a MacBook Pro M2 Pro. Many Thanks and Best Regards Francesco

I have a DriverKit dext that implements a virtual SCSI HBA (no physical hardware). Because a bare IOUserSCSIParallelInterfaceController has no provider to match, the bundle ships two IOKitPersonalities: Bootstrap — IOClass IOUserService, IOProviderClass IOUserResources, IOResourceMatch IOKit. In Start() it does SetProperties({NvmeOfSCSIHBA: true}) + RegisterService(), publishing itself as a nub. Controller — IOClass IOUserSCSIParallelInterfaceController, IOProviderClass IOUserService, IOPropertyMatch {NvmeOfSCSIHBA: true} — it matches the bootstrap nub. This loads and runs correctly. The problem is upgrades. Activating a higher CFBundleVersion via OSSystemExtensionRequest.activationRequest (in-place replace) always defers the old version's termination to reboot. The new version reaches [activated enabled] but never starts; the old process keeps running until reboot. From sysextd/kernelmanagerd: kernelmanagerd Dext … v15 … is being replaced and cannot be terminated right away sysextd delegate returns Error Domain=OSSystemExtensionErrorDomain Code=101 "…is being replaced", assumes responsibility for old version …, keeping old version 15 sysextd turning the responsibility for termination of …, version 15 over to delegate (with uninstallation at the next reboot) sysextd a category delegate declined to terminate extension with identifier: … sysextd v15 terminating_for_uninstall → terminating_for_upgrade_via_delegate Key observation: this defers even on a fresh boot where the dext was never opened — no app/daemon ever opened the IOUserClient, no I/O, nothing attached beyond the controller↔nub match. So it does not appear to be a "client still holds it open" / busy-state situation; the driver_extension category delegate declines the moment it's a replacement. What I've tried: In-place activationRequest (replace): always defers to reboot (above). deactivationRequest (standalone): the request hangs — no delegate callback at all (waited ~13 min), even with no client open. Disconnecting all clients first (graceful Stop() that cancels its dispatch queues and completes async) does not change the replace deferral. My understanding from the docs/forums is that the normal reboot-free replace relies on the backing device being disconnected/reconnected to quiesce the old dext (thread 677040). My controller matches a persistent IOUserResources-backed nub that never detaches, so there's no equivalent quiesce point. Questions: For a dext whose only provider is a self-published IOUserResources nub (no detachable hardware), is reboot-free replacement structurally impossible — i.e. is the Code=101 "is being replaced" defer inherent to this matching pattern? Is the supported way to live-upgrade such a dext to deactivationRequest → (on .completed) → activationRequest rather than an in-place replace? If so, what makes a deactivationRequest complete in-session vs. defer to reboot for an IOUserResources-matched dext — and what would cause it to hang with no delegate callback? (Daemon's IOUserClient is closed; the controller's Stop() cancels its queues and completes.) Should the dext itself proactively tear down the published nub (e.g. terminate the bootstrap IOService) before/at upgrade so the controller detaches — or does that just re-match the still-staged old personalities and relaunch the old version? Is there a recommended pattern for a virtual (hardwareless) DriverKit HBA that needs in-field, reboot-free version updates, or is reboot genuinely required for this class of dext? Environment: macOS 27 (Tahoe)

I’m prototyping a personal-use system that lets an iPhone with a physically attached controller act as an input device for a Mac. End goal: Use the iPhone as the transport and sensor host Use the attached physical controller for buttons/sticks Map the iPhone gyroscope to the controller’s right stick to get gyro aim in Mac games / cloud-streamed games such as GeForce NOW that don't support the gyro. What I’m trying to understand is whether Apple supports any path for this on macOS that does NOT require restricted entitlements or paid-program-only capabilities. What I’ve already found: CoreHID virtual HID device creation appears to require com.apple.developer.hid.virtual.device HIDDriverKit / system extensions appear to require Apple-granted entitlements as well GCVirtualController does not seem to solve the problem because I need a controller-visible device that other apps can see, not just controls inside my own app So my concrete question is: Is there any supported, entitlement-free way for a personal macOS app to expose a game-controller-like input device that other apps can consume system-wide? If not, is the official answer that this class of solution necessarily requires one of: CoreHID with restricted entitlement HIDDriverKit/system extension entitlement some other Apple-approved framework or program I’m missing I’m not asking about App Store distribution. This is primarily for local/personal use during development. I’m trying to understand the supported platform boundary before investing further. Any guidance on the recommended architecture for this use case would be appreciated.

I'm building a virtual audio device using the HAL Plugin (AudioServerPlugin) API on macOS. The plugin loads correctly, WriteMix is called with non-zero audio data, but Plugin_StartIO is never called from my app's AUHAL input client. Environment: macOS 26.5 Xcode (latest) Bundle ID: com.private.SubON Plugin installed at: /Library/Audio/Plug-Ins/HAL/SubONHALPlugin.driver What works: Plugin loads and is visible as "SubON Virtual Device" Plugin_AddDeviceClient is called with bundleID=com.private.SubON WriteMix is called with non-zero maxSrc values (audio is reaching the plugin) AUHAL setup completes: EnableIO input=1 output=0, CurrentDevice set correctly, AudioUnitInitialize succeeds pre-start readback confirms: currentDevice matches, enableIOIn=1 What doesn't work: Plugin_StartIO is never called from the SubON.app input client WillDoIOOperation is never called ReadInput is never called maxAmplitude in the input tap is always 0.0 AUHAL setup code (Swift): AudioUnitUninitialize(auhal) AudioUnitSetProperty(auhal, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &one, size) AudioUnitSetProperty(auhal, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &zero, size) AudioUnitSetProperty(auhal, kAudioOutputUnitProperty_CurrentDevice, kAudioUnitScope_Global, 0, &deviceID, size) AudioUnitInitialize(auhal) HAL Plugin — WillDoIOOperation: outWillDo = true; outWillDoInPlace = true; Returns true for both ReadInput and WriteMix. Observation: Even when selecting "SubON Virtual Device" as the system input device in System Settings, Plugin_StartIO is still never called. Any ideas what could prevent Plugin_StartIO from being called despite AUHAL configuration appearing correct?

Hopefully a very quick question for anyone familiar with IOUserSCSIParallelInterfaceController - what is the right initialization to implement: init () override; Start (IOService * provider) override; UserInitializeController () override; something else Seems #3 is required, but guidance varies on the others, undoubtedly bc IOUserSCSI.. implements a lot of things beyond the usual DriverKit structure. Thanks in advance for any help. (We're trying to implement a driver for a legacy SCSI controller).

I've updated to macOS Golden Gate beta, now I can't print. I'm using HP printer. Anyone plz help.

I want to implement a function to generate a report in the form of pages using the model data of the iOS application. I didn't find the relevant API. Please help me find a relevant SDK and some examples. Thanks.

Hello, I have a device like a gas meter or an electricity meter and it has: an optical interface IEC 62056-21 (IEC-1107) with support for speeds up to 115,200 Bd. On Windows and Android, we use a cable that has an optical interface and on the other end we connect USB A to the PC and to the Android via an OTG to USB adapter. The cable contains a chip from FTDI FT230XQ. I have an application in MAUI where I want to connect this cable to the 10th generation iPad and communicate similarly to, for example, via the COM5 port on the PC. When the port opens, I send a query and get a response. Is it possible, what should I do for this? What about Apple certification of cables? Is it possible to send a packet from MAUI via the USB C port via the cable and then receive and process the packet again? What about MFi? I found this: https://redpark.com/usb-c-serial-cable/ Please can you give me some idea or expert to this topic? Thanks, Roman

We are developing an IOUserSCSIParallelInterfaceController driver for a legacy controller. After completing init() successfully, no other methods are called before a DriverKit assert failure - .driver.dext) Assertion failed: (notsync || !remote || (msgid == IOService_Start_ID) || queue->OnQueue()), function Invoke, file uioserver.cpp, line 1654. - that leads immediately to "IOPCIDevice::ClientCrashed_Impl() for client " . This appears to be because the framework is attempting a SetPowerState()' during DEXT load, which is delivered off-queue and panics in OSMetaClassBase::Invoke (uioserver.cpp`) before any other dext method runs. Apple Silicon Mac, macOS 26 (DriverKit 25.1 SDK), Xcode 26.x. Expected: The SetPowerState() power-up is delivered on the driver object's dispatch queue (or otherwise handled by the framework), allowing the dext's SetPowerState override to run, ACK via super::SetPowerState(powerFlags, SUPERDISPATCH), and proceed to UserInitializeController. Actual behavior: init() completes (our trace logs init then completed init) Neither Start_Impl nor SetPowerState_Impl ever executes Instead the process fails with the assertion above , IOPCIDevice::ClientCrashed_Impl() reports "client … does not have open session … skipping recovery". The dext crash-loops ("Driver … has crashed N time(s)"). Any suggestions?

I have a product that currently communicates to a piece of proprietary Medical hardware via USB. We have a driver created with USBDriverKit that is a hard requirement for this product to function. Currently, we are delivering an iPadOS application that utilizes the driver. Our next step is to create an SDK that includes all of the Frameworks and the driver utilized by the application. Since the driver is a system extension that lives in the application, how do we bundle it with our SDK and make it available for use by third-parties?

Hello everyone, We are in the process of migrating a high-performance storage KEXT to DriverKit. During our initial validation phase, we noticed a performance gap between the DEXT and the KEXT, which prompted us to try and optimize our I/O handling process. Background and Motivation: Our test hardware is a RAID 0 array of two HDDs. According to AJA System Test, our legacy KEXT achieves a write speed of about 645 MB/s on this hardware, whereas the new DEXT reaches about 565 MB/s. We suspect the primary reason for this performance gap might be that the DEXT, by default, uses a serial work-loop to submit I/O commands, which fails to fully leverage the parallelism of the hardware array. Therefore, to eliminate this bottleneck and improve performance, we configured a dedicated parallel dispatch queue (MyParallelIOQueue) for the UserProcessParallelTask method. However, during our implementation attempt, we encountered a critical issue that caused a system-wide crash. The Operation Causing the Panic: We configured MyParallelIOQueue using the following combination of methods: In the .iig file: We appended the QUEUENAME(MyParallelIOQueue) macro after the override keyword of the UserProcessParallelTask method declaration. In the .cpp file: We manually created a queue with the same name by calling the IODispatchQueue::Create() function within our UserInitializeController method. The Result: This results in a macOS kernel panic during the DEXT loading process, forcing the user to perform a hard reboot. After the reboot, checking with the systemextensionsctl list command reveals the DEXT's status as [activated waiting for user], which indicates that it encountered an unrecoverable, fatal error during its initialization. Key Code Snippets to Reproduce the Panic: In .iig file - this was our exact implementation: class DRV_MAIN_CLASS_NAME: public IOUserSCSIParallelInterfaceController { public: virtual kern_return_t UserProcessParallelTask(...) override QUEUENAME(MyParallelIOQueue); }; In .h file: struct DRV_MAIN_CLASS_NAME_IVars { // ... IODispatchQueue* MyParallelIOQueue; }; In UserInitializeController implementation: kern_return_t IMPL(DRV_MAIN_CLASS_NAME, UserInitializeController) { // ... // We also included code to manually create the queue. kern_return_t ret = IODispatchQueue::Create("MyParallelIOQueue", kIODispatchQueueReentrant, 0, &ivars->MyParallelIOQueue); if (ret != kIOReturnSuccess) { // ... error handling ... } // ... return kIOReturnSuccess; } Our Question: What is the officially recommended and most stable method for configuring UserProcessParallelTask_Impl() to use a parallel I/O queue? Clarifying this is crucial for all developers pursuing high-performance storage solutions with DriverKit. Any explanation or guidance would be greatly appreciated. Best Regards, Charles

I'm investigating supporting a touchscreen digitizer on macOS. I'd like to receive multi-touch reports from the device, and have them intercepted by my app. I also want to suppress the default absolute positioning 'mouse' behavior of the touch screen. The device exposes three HID interface: #0 - multi-touch (PrimaryUsagePage 0xD, PrimaryUsage 4) #1 - vendor-specific #2 - single-touch (PrimaryUsagePage 1, PrimaryUsage 2) I've only been able to achieve half of my goal using a HIDDriverKit dext - I can outmatch the OS for the single-touch HID interface and ignore its 7-byte single-touch reports. However, although I can match to the multi-touch interface, I never see any reports at all there, as if the OS never polls the interrupt endpoint. On Windows, the device "just works" - I've traced its behavior in Wireshark. The OS doesn't do any special setup, it sends no SET_FEATURE commands, it just reads from the multi-touch interrupt endpoint, where it receives 54-byte reports. Windows doesn't even get any 7-byte single-touch reports. On macOS, I managed to use Wireshark on an old Intel Mac, where I can still use XHC20 for logging. Here, macOS tries to read from all the interrupt endpoints for all the HID interfaces, and the digitizer only responds on the single-touch interface. MSDN's documentation for multi-touch support is quite unhelpful here, because it just says "use the OS driver", but doesn't detail how a digitizer switches between multi-touch and single-touch mode. If I were making a digitizer, I'd send reports on both interfaces, expecting the OS to read the single- or multi-touch interface as required. Although unlikely, it seems that this digitizer changes its behavior based on how it is accessed. I can outmatch the USB interface for the single-touch reports, so that the OS HID driver doesn't even see it. That doesn't change the device behavior. The HIDDriverKit APIs I use imply setting up an interrupt read. I call Open on the interface, and implement a ReportAvailable callback. This works for the single-touch interface, but I get no reports on the multi-touch interface. All the calls with return values return kIOReturnSuccess. Does anyone know how multi-touch digitizers switch between single- and multi-touch mode (if indeed they have a mode at all), or why macOS apparently doesn't even read the multi-touch interrupt end point? Does anyone know how I can ensure that my HID driver actually reads the interrupt endpoint on the HID interface it is matched to? Does macOS deliberately prevent access to multi-touch HID interfaces?

Does Virtualization.framework support delegating a Thunderbolt/PCIe device to a Linux guest VM running on Apple Silicon? We're developing a custom PCIe device and would like to iterate on the driver in a Linux VM environment on the same host.

Can a Thunderbolt device dynamically expose logical child devices to macOS and control their connection and disconnection lifecycle, independently of the physical device connection?

Le jeu genshin impact crash direct au lancement impossible de joué j‘ai eu beau décharger l‘appli et réessayer de la télécharger elle bug et crash direct

Hello, I am using an iPhone 15 Pro and I am currently running iOS 27 Developer Beta. I have a problem with Apple Intelligence. The “Apple Intelligence & Siri” menu does not appear in Settings. I only have the standard Siri menu, and Apple Intelligence features such as Writing Tools, summarization, and other AI functions are unavailable. Here is my current setup: Device: iPhone 15 Pro Software: iOS 27 Developer Beta iPhone Language: English (US) Siri Language: English (US) Region: United States Apple Account Region: Turkey Birth Year: 2007 What makes this situation confusing is that this exact same device previously belonged to my father. I personally saw and used the Apple Intelligence settings and features on this phone before I signed in with my own Apple Account. After signing into my own Apple Account, Apple Intelligence completely disappeared. The “Apple Intelligence & Siri” menu is no longer available and only the regular Siri menu remains. I have already tried the following: Restarted the device Changed the device language to English (US) Changed the region to United States Freed up a significant amount of storage space Updated to iOS 27 Developer Beta My device model number is MV923CH/A. Could this be related to my Apple Account, the device’s regional variant, or an issue with iOS 27 Beta? Has anyone experienced something similar or found a solution? Thank you.

I need a bit more support. Per Apple’s guidance, our dext’s hosting app checks to see if the dext is installed, and if it is not installed, it will register the dext. I am going to refer to this as “auto registration.” I have also added a menu option to register the dext, which I am going to call “manual registration.” The manual registration works. The user is prompted to “Allow” the dext to be loaded, and things proceed normally. The auto-registration does not work. It produces an error response that is not helpful: Request did fail with Error 1 (The operation couldn’t be completed. (OSSystemExtensionErrorDomain error 1.)) Registration failed, unknown error. They execute the exact same code path – the auto registration calls the menu option’s function that executes from user selection. When comparing the sysextd logs, they differ starting at “Advancing from validating to validating_by_category.” The manual registration has a trace that reads: got reply from com.apple.system_extension.driver_extension... The auto registration does not get this reply. Attached are the two logs. This is Sonoma 14.7.6, the earliest OS we must support. Any suggestions on what is happening or how to fix it so that auto registration can work? Validate_by_category failure trace Validate_by_category success trace

Hi Kevin, I'm starting this new thread to focus on alignment optimization and recalibrating our HBA constraints. Following up on your suggestion about UserReportHBAConstraints and alignment optimization, here are our current DEXT settings: Via UserReportHBAConstraints(): kIOMaximumSegmentCountRead/WriteKey: 129 kIOMaximumSegmentByteCountRead/WriteKey: 65,536 (64 KB) kIOMinimumSegmentAlignmentByteCountKey: 4 bytes kIOMaximumSegmentAddressableBitCountKey: 32 kIOMinimumHBADataAlignmentMaskKey: 0 Via SetProperties() (additional injection): kIOMaximumByteCountRead/WriteKey: 524,288 (512 KB) kIOMaximumBlockCountRead/WriteKey: 1,024 We inherited the segment count (129) and max I/O length (512 KB) from our legacy KEXT, which were originally calculated based on a 4 KB segment size (Max I/O 512 KB / 4 KB + 1 = 129). The current alignment value of 4 was essentially a placeholder, as the legacy hardware didn't enforce strict page-level alignment. Given that our testing is on Apple Silicon, we are considering increasing kIOMinimumSegmentAlignmentByteCountKey to 16,384 (16 KB) to match the native page size. However, I have two specific questions regarding this: Stripe Size vs. Page Size: Our RAID stripe size is typically larger than 16 KB (e.g., 64 KB or 128 KB). Should we be aligning the system to the RAID stripe size for hardware efficiency, or is it more critical to stick to the 16 KB page size to optimize the IOMMU/DART mapping overhead in DriverKit? Recalibration: If we increase the alignment to 16 KB, should we also adjust the kIOMaximumSegmentByteCount to match (i.e., 16 KB), or is it better to keep it at 64 KB to allow fewer, larger segments per I/O? We suspect that the 38% gain we saw in 4 KB Random Reads might improve even further if we fix this alignment bottleneck. Looking forward to your thoughts. Best regards, Charles

I'm working on hardware that communicates wireless and wired with mobile systems. Anything non-i[Pad]OS we can connect via USB and achieve great bandwidth, in situations where this is necessary. Since i[pad]OS does not support FTDI class compliant devices through USB (and also omits the IOUSB framework), I wonder whether we have a way to "work around" this, e.g. how about (ab)using another protocol that i[pad]OS allows? Concretely, would you think it's possible to tunnel our serial data stream via USBHID?

Hello everyone, We're working on an iOS app that needs to connect to a non-Apple pre-operating system using USB for serial communication. Our goal is to send and receive data between an iPhone and a UEFI-based system directly over USB. We've created a proof of concept using the USBMux protocol, which let us exchange basic messages. However, we're running into problems with the USB endpoint setup. In some cases, the USB communication doesn't start or stay connected. Since this is for a pre-boot environment, it might not fit into the usual iOS USB communication frameworks. We're looking for help with the following: Any guidance or documentation on setting up USB serial communication between an iPhone and a non-Apple pre-boot system Information on system APIs, frameworks, or protocols that iOS supports for direct USB communication in this scenario Access to official USBMux documentation or specs to understand its limitations and capabilities better Whether this communication requires MFi certification or if there are other Apple-supported interfaces we can use Thank you!