Understand the role of drivers in bridging the gap between software and hardware, ensuring smooth hardware functionality.

Drivers Documentation

Post

Replies

Boosts

Views

Activity

Adjust Latency Timer for the AppleUSBFTDI Driver
How do I adjust the latency timer for the AppleUSBFTDI driver? I am developing an app in Swift using Xcode on a MacBook Pro M1 running Big Sur, for clinical brain-computer interface (BCI) research. The app needs very low-latency streaming from an external USB device. The external device is a headset which connects via Bluetooth to an FT231X chip mounted on a USB-Serial dongle. The FT231X chip reads timestamped EEG data from the headset. The issue is that the AppleUSBFTDI driver is buffering the packets coming in from the headset, which causes jitter in the timestamps. Typically, with proprietary drivers from FTDI, the solution is to reconfigure them to reduce the latency timer to 1ms. The Info.plist is edited to add new key/value pairs. Is there a similar solution for Apple's built-in driver?
1
1
990
Sep ’21
Launching Network System Extension from LaunchAgent
In another question on this forum (https://developer.apple.com/forums/thread/124775) eskimo stated that launching a system extension from an daemon is not the right approach and that the OSSystemExtensionRequest.activationRequest API should be called from an App. My question is, does this same restriction apply to a LaunchAgent started App? If so, to ensure activation as soon as possible is the only option to use a SMLoginItemSetEnabled helper to start the App on login?
5
0
1.4k
Mar ’22
is XPC from app to CMIOExtension possible?
I built an app which hosts a CMIOExtension. The app works, and it can activate the extension. The extension loads in e.g. Photo Booth and shows the expected video (a white horizontal line which moves down the picture). I have a couple of questions about this though. The sample Camera Extension is built with a CMIOExtension dictionary with just one entry, CMIOExtensionMachServiceName which is $(TeamIdentifierPrefix)$(PRODUCT_BUNDLE_IDENTIFIER) This Mach service name won't work though. When attempting to activate the extension, sysextd says that the extensions has an invalid mach service name or is not signed, the value must be prefixed with one of the App Groups in the entitlement. So in order to get the sample extension to activate from my app, I have to change its CMIOExtensionMachServiceName to <my team ID>.com.mycompany.my-app-group.<myextensionname> Is this to be expected? The template CMIOExtension generates its own video using a timer. My app is intended to capture video from a source, filter that video, then feed it to the CMIOExtension, somehow. The template creates an app group called "$(TeamIdentifierPrefix)com.example.app-group", which suggests that it might be possible to use XPC to send frames from the app to the extension. However, I've been unable to do so. I've used NSXPCConnection * connection = [[NSXPCConnection alloc] initWithMachServiceName:, using the CMIOExtensionMachServiceName with no options and with the NSXPCConnectionPrivileged option. I've tried NSXPCConnection * connection = [[NSXPCConnection alloc] initWithServiceName: using the extension's bundle identifier. In all cases when I send the first message I get an error in the remote object proxy's handler: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named <whatever name I try> was invalidated: failed at lookup with error 3 - No such process." According to the "Daemons and Services Programming Guide" an XPC service should have a CFBundlePackageType of XPC!, but a CMIOExtension is of type SYSX. It can't be both. Does the CMIOExtension loading apparatus cook up a synthetic name for the XPC service, and if so, what is it? If none, how is one expected to get pixel buffers into the camera extension?
19
0
8.0k
May ’22
CoreMediaIO Camera Extension: custom properties?
I struggle to add custom properties to my streams as described in the WWDC22 video https://developer.apple.com/videos/play/wwdc2022/10022/ minute 28:17 The speaker describes using this technique in his CIFilterCam demo (would the source code be available please?) to let the app control which filter the extension should apply. Presumably, there's thus a way to: 1 - define a custom property in the camera extension's stream/device/provider? 2 - be able to use CoreMediaIO (from Swift?) in the app in order to set values of that custom property. This is not documented anywhere I could find. Help and sample code would be greatly appreciated. Thank you. Laurent
14
0
4.1k
Jun ’22
CoreMedia I/O Camera Extension Installation Error (Invalid Signature)
Hi! I'm trying to move from CoreMedio I/O DAL Plug-In to CoreMedia I/O camera extensions, announced in macOS 12.3. I created a test extension, placed it inside my app bundle into Contents/Library/SystemExtensions and signed with codesigning certificate. But when I try to install my extension from inside my app, using this code (Swift): func requestActivation() { guard case .idle = status else { fatalError("Invalid state") } print("Requesting activation of extension \"\(extensionIdentifier)\"") let req = OSSystemExtensionRequest.activationRequest(forExtensionWithIdentifier: extensionIdentifier, queue: DispatchQueue.main) req.delegate = self OSSystemExtensionManager.shared.submitRequest(req) status = .requested } I'm getting an error: OSSystemExtensionErrorDomain error 8: Code Signature Invalid which is rather generic. Can anybody tell me what I am doing wrong? Or at least propose some steps to find it out? I'm posting here entitlements and codesign output for my extension and containing application for further information. kdg@admins-Mac-mini SystemExtensions % codesign -d --entitlements - ./com.visicom.VirtualCamera.avextension.systemextension Executable=/Applications/VirtualCamera.app/Contents/Library/SystemExtensions/com.visicom.VirtualCamera.avextension.systemextension/Contents/MacOS/com.visicom.VirtualCamera.avextension [Dict] [Key] com.apple.security.app-sandbox [Value] [Bool] true [Key] com.apple.security.application-groups [Value] [Array] [String] 6SUWV7QQBJ.com.visicom.VirtualCamera kdg@admins-Mac-mini /Applications % codesign -d --entitlements - ./VirtualCamera.app Executable=/Applications/VirtualCamera.app/Contents/MacOS/VirtualCamera [Dict] [Key] com.apple.developer.system-extension.install [Value] [Bool] true [Key] com.apple.security.app-sandbox [Value] [Bool] true [Key] com.apple.security.application-groups [Value] [Array] [String] 6SUWV7QQBJ.com.visicom.VirtualCamera [Key] com.apple.security.files.user-selected.read-only [Value] [Bool] true kdg@admins-Mac-mini SystemExtensions % codesign -dvvv ./com.visicom.VirtualCamera.avextension.systemextension Executable=/Applications/VirtualCamera.app/Contents/Library/SystemExtensions/com.visicom.VirtualCamera.avextension.systemextension/Contents/MacOS/com.visicom.VirtualCamera.avextension Identifier=com.visicom.VirtualCamera.avextension Format=bundle with Mach-O universal (x86_64 arm64) CodeDirectory v=20500 size=1553 flags=0x10700(hard,kill,expires,runtime) hashes=37+7 location=embedded Hash type=sha256 size=32 CandidateCDHash sha256=25bd80657bfd6e0ab95467146c7b532817e9e520 CandidateCDHashFull sha256=25bd80657bfd6e0ab95467146c7b532817e9e5209fd50b0cb7ceef40dcfb40e8 Hash choices=sha256 CMSDigest=25bd80657bfd6e0ab95467146c7b532817e9e5209fd50b0cb7ceef40dcfb40e8 CMSDigestType=2 CDHash=25bd80657bfd6e0ab95467146c7b532817e9e520 Signature size=9006 Authority=Developer ID Application: Visicom Media Inc. (6SUWV7QQBJ) Authority=Developer ID Certification Authority Authority=Apple Root CA Timestamp=7 Jul 2022, 21:49:32 Info.plist entries=23 TeamIdentifier=6SUWV7QQBJ Runtime Version=12.3.0 Sealed Resources version=2 rules=13 files=0 Internal requirements count=1 size=200 kdg@admins-Mac-mini /Applications % codesign -dvvv ./VirtualCamera.app Executable=/Applications/VirtualCamera.app/Contents/MacOS/VirtualCamera Identifier=com.visicom.VirtualCamera Format=app bundle with Mach-O universal (x86_64 arm64) CodeDirectory v=20500 size=1989 flags=0x10700(hard,kill,expires,runtime) hashes=51+7 location=embedded Hash type=sha256 size=32 CandidateCDHash sha256=31e15fbbd436a67a20c5b58c597d8a4796a67720 CandidateCDHashFull sha256=31e15fbbd436a67a20c5b58c597d8a4796a6772020308fb69f4ee80b4e32788b Hash choices=sha256 CMSDigest=31e15fbbd436a67a20c5b58c597d8a4796a6772020308fb69f4ee80b4e32788b CMSDigestType=2 CDHash=31e15fbbd436a67a20c5b58c597d8a4796a67720 Signature size=9006 Authority=Developer ID Application: Visicom Media Inc. (6SUWV7QQBJ) Authority=Developer ID Certification Authority Authority=Apple Root CA Timestamp=7 Jul 2022, 21:58:09 Info.plist entries=20 TeamIdentifier=6SUWV7QQBJ Runtime Version=12.3.0 Sealed Resources version=2 rules=13 files=4 Internal requirements count=1 size=188 Thanks in advance!
8
0
2.4k
Jul ’22
DriverKit driver doesn't appear in Settings when installed with iPad app
I'm working on a DriverKit driver. I have it running on macOS, including a very simple client app written in SwiftUI. Everything is working fine there. I've added iPadOS as a destination for the app as demonstrated in the WWDC video on DriverKit for iPadOS. The app builds and runs on my iPad, as expected (after a little work to conditionalize out my use of SystemExtensions.framework for installation on macOS). However, after installing and running the app on an iPad, the driver does not show up in Settings->General, nor in the app-specific settings pane triggered by the inclusion of a settings bundle in the app. I've confirmed that the dext is indeed being included in the app bundle when built for iPadOS (in MyApp.app/SystemExtensions/com.me.MyApp.MyDriver.dext). I also can see in the build log that there's a validation step for the dext, and that seems to be succeeding. I don't know why the app isn't being discovered -- or in any case surfaced to the user -- when the app is installed on the iPad. Has anyone faced this problem and solved it? Are there ways to troubleshoot installation/discovery of an embedded DriverKit extensions on iOS? Unlike on macOS, I don't really see any relevant console messages.
4
1
1.6k
Feb ’23
Subclassing from IOUserUSBSerial
Hey! I'am trying to write my own driver for usb serial device. I'am trying to subclass from IOUserUSBSerial #include <DriverKit/IOService.iig> #include <USBSerialDriverKit/IOUserUSBSerial.iig> class NewDriver: public IOUserUSBSerial { public:     virtual kern_return_t     Start(IOService * provider) override; }; but get a lot of errors such as   "IOUserUSBSerial::handleRxPacket(unsigned char*&, unsigned int&)", referenced from:       vtable for NewDriver in NewDriver.iig.o   "IOUserUSBSerial::handleInterruptPacket(unsigned char const*, unsigned int)", referenced from:       vtable for NewDriver in NewDriver.iig.o   "IOUserUSBSerial::free()", referenced from:       vtable for NewDriver in NewDriver.iig.o   "IOUserUSBSerial::init()", referenced from:       vtable for NewDriver in NewDriver.iig.o   "IOUserUSBSerial::initWith(IOBufferMemoryDescriptor*)", referenced from:       vtable for NewDriver in NewDriver.iig.o   "IOUserUSBSerial::_Dispatch(IOUserUSBSerial*, IORPC)", referenced from:       NewDriver::Start_Impl(IOService*) in NewDriver-e6d71af2158103084ce0c1eba7c6088d.o       NewDriver::_Dispatch(NewDriver*, IORPC) in NewDriver.iig.o   "vtable for IOUserSerial", referenced from:       IOUserSerial::IOUserSerial() in NewDriver.iig.o   NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.   "vtable for IOUserUSBSerial", referenced from:       IOUserUSBSerial::IOUserUSBSerial() in NewDriver.iig.o   NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.   "non-virtual thunk to IOUserUSBSerial::free()", referenced from:       vtable for NewDriver in NewDriver.iig.o   "non-virtual thunk to IOUserUSBSerial::init()", referenced from:       vtable for NewDriver in NewDriver.iig.o   "non-virtual thunk to IOUserUSBSerial::initWith(IOBufferMemoryDescriptor*)", referenced from:       vtable for NewDriver in NewDriver.iig.o   "non-virtual thunk to IOUserUSBSerial::handleRxPacket(unsigned char*&, unsigned int&)", referenced from:       vtable for NewDriver in NewDriver.iig.o   "non-virtual thunk to IOUserUSBSerial::handleInterruptPacket(unsigned char const*, unsigned int)", referenced from:       vtable for NewDriver in NewDriver.iig.o ld: symbol(s) not found for architecture x86_64 If I making any implementations of this methods errors staying on. What Im doing wrong? Is there anywhere examples for USBSerialDriverKit? Didn't find anything on github
2
0
1.1k
Mar ’23
Metal Device Architecture on macOS versions before Sonoma
Hello, The latest version of Metal (on macOS 14) seems to have the instance property for the Metal device architecture. I was curious how this could be achieved on versions of macOS prior to 14 programatically? xcrun metal-arch The above command provides exactly what I need. I was thinking that I could use Metal and IOKit to grab the architecture, but I am lead to believe that there is some kind of mapping in the metal-arch tool and it may not be that easy. Any help would be greatly appreciated. Thanks.
1
0
668
Dec ’23
IOServiceOpen Keeps Returning kIOReturnUnsupported
I have a custom HID device that works on Windows totally fine with the default HID driver. The HID device knows how to accept string commands to control it and respond accordingly. I am trying to control it on Mac using IOKit. I am able to get the io_service_t reference to the IOHIDInterface for the device from the I/ORegistery. I use this to instantiate a class to represent the device. But when I try to establish a connection to the service, I keep getting -536870201 which corresponds to kIOReturnUnsupported. I'm not entirely sure what I am doing wrong here and I wasn't able to find anything online that could really help.
1
0
703
Dec ’23
Control HID USB Device from iPad?
I have a custom HID USB device that I can control on Mac with IOKit via the default HID MacOS driver. I am using IOHIDManager to detect it and send reports to it. I would like to extend this capability to iPad but the full IOKit framework is not supported on iOS/iPadOS. I saw that USBDriverKit is now supported on iPads with an M1 chip or newer. But, both MacOS and Windows can operate the device with their generic HID driver. As such, having to create a whole custom driver to interact with an HID device on iOS is really overkill. Would registering it in the MFi Program and operating it with the External Accessory framework be the correct route to take here? Or is there another framework for controlling HID devices on iPad over USB that I am not aware of?
2
0
1.4k
Dec ’23
Help needed with lldb - attach to Mac after a kernel panic
I am trying to debug a kernel panic in our kext. I can attach to the target Mac over ethernet if I: cause an NMI using add an IOPanic call to my kext and cause it to be executed use Dtrace to invoke a panic However if I reproduce the kernel panic which I am investigating, the Mac just restarts. How can I make the Mac wait for me to attach with lldb rather than restarting? My target configuration is: Mac is 2021 M1 Pro 14" MacBook Pro macOS 14.2 (23C64) Network: Apple Thunderbolt 3 <-> Thunderbolt 3 adapter + Apple Thunderbolt 2 to ethernet adapters Boot-args = "debug=0x44 wdt=-1 kdp_match_name=en8" (I have also tried debug=0x104C0C)
2
0
803
Dec ’23
Serial port communication from iOS app to device
Hello, We have a device that acts as a ***** device and communicates with a master over data sent over a USB serial port over a wired connection. We are trying to develop an Application on iOS that will enable us to use the USB connection between iPhone and our device. Kindly suggest to us what is the way to achieve this. A few searches let us know that Apple's MFi program needs to be enrolled. Please let us know how this works and where could we find process for the same. I thank you in advance! Makarand
2
1
1.4k
Dec ’23
Local Signging of a driverkit extension.
I am new to macOS development and presently tearing my hair out trying to get a driverkit extension to build. I have tried following the instructions here: https://developer.apple.com/documentation/driverkit/communicating_between_a_driverkit_extension_and_a_client_app namely, disabling SIP, but I am still unable to get my extension to build. The instructions say to set the code signing identity to "Sign to Run Locally" for all three targets, but this is not listed as an option for the driver extension.
1
0
829
Dec ’23
What are command line tools?
I was trying to hide some external drives from desktop, I know I can do it from finder preferences, but it will hide all my external drives from desktop. I want drive A, B, C to be visible on desktop but don't want drive D to be visible. Some website suggest this solution: sudo SetFile -a V /Volumes/"Drive Name" but it says I need command line tools, since I was in terminal, and prompt come from MacOS itself, I stared installation. But what are this tools actually is it sahe to install it? And why this tool taking 2.35GB of storage just to hide one icon from desktop?
1
0
707
Dec ’23