the source code of memory_pressure is here: https://github.com/apple-oss-distributions/system_cmds/blob/e0c267e80e451b9441ec4f4bb05dd72f0b49d596/memory_pressure/memory_pressure.c

Kevin, thanks for the suggestion. Unfortunately, it didn't work. I can put a different value for bInterfaceProtocol into the USB Device Info dictionary of the IOUSBMassStorageDriverNub, but that doesn't affect how the rest of the stack behaves. Whether I put 80 or 98 into bInterfaceProtocol, I always end up with a IOUSBMassStorageUASDriver attached to the IOUSBMassStorageDriverNub. I don't think modifying properties is going to work, unless there is some property I can add to the interface or the device that tells the stack "don't use alternate 1" or "always use alternate 0", which would require direct support from the USB stack.

You're in the wrong place to ask questions like these. support.apple.com would be more appropriate.

I tried making a codeless dext which matches to my IOUSBHostInterface. It has a plist that looks like this: CFBundleIdentifierKernel = com.apple.kpi.iokit // not sure if this is required IOClass = AppleUSBHostMergeProperties // uses IOProviderMergeProperties IOMatchCategory = $(PRODUCT_BUNDLE_IDENTIFIER) // makes its matching unique IOProviderClass = IOUSBHostInterface // what I want to match against IOUserClass = force_alt0 // not sure I need this, because we don't need a user-space process at all // required properties for matching to a IOUSBHostInterface, // see https://developer.apple.com/library/archive/qa/qa1076/_index.html idProduct = x // my product's usb product ID, as a Number idVendor = y // my product's usb vendor ID, as a Number bInterfaceNumber = 0 bConfigurationValue = 1 IOProviderMergeProperties = { bInterfaceProtocol = 80 // 0x50 sentinelProperty = "I am just a string" } I can see in the IORegistry that my sentinelProperty is applied to the interface, but bInterfaceProtocol is not. If I look at the IORegistry without my codeless dext, I see this hierarchy IOUSBInterface bInterfaceProtocol = 0x62 IOUSBMassStorageInterfaceNub, bInterfaceProtocol = 0x50 IOUSBMassStorageDriverNub, bInterfaceProtocol = 0x62 IOUSBMassStorageUASDriverNub, bInterfaceProtocol = 0x62 with my codeless dext, I see the same classes, with the same values of bInterfaceProtocol. I expect that tweaking the bInterfaceProtocol value on the IOUSBHostInterface at driver match time doesn't make any difference. Something in the USB stack that matches later, perhaps the IOUSBMassStorageDriverNub, is looking at the IOUSBHostInterface and making its own decision about what alternate interface to set, which causes IOUSBHostInterface to set its own bInterfaceProtocol property value. The value I designate in my IOProviderMergeProperties dictionary may well be briefly applied to the IOUSBHostInterface, but is later overwritten. Is there some other way to convince the OS to not use alternate interface 1?

Hi. Welcome to these forums, which are for developers to communicate with other developers (some of whom may work for Apple) about issues with developing software for Apple platforms. You're not going to get much traction here. Your issue seems to be a feature suggestion for Apple software. Apple have a web address where you can submit such feedback: https://www.apple.com/feedback/ It helps if you clearly identify what platform (macOS, iOS, iPadOS, watchOS, tvOS...) you are referring to, and clearly describe what feature you think is missing (close all what?). If you believe you have found a bug in Apple software, you can use this address: https://feedbackassistant.apple.com or the Feedback Assistant app.

This has often happened to me with code which is incorrect but not glaringly so. I've found that using an LLM is useful here. Just ask it "why can't the Swift compiler type check this in reasonable time: " and append the code. An LLM isn't as hard-nosed as a compiler; it can spot common errors like extra or missing commas. It might be worth suggesting this as an Xcode feature. Just as the compiler constantly runs in the background as you type, an LLM could constantly examine your code and point out oddities - things that might even compile, but are likely unintended, or possible reasons for compiler error messages.

look in ~/Library/Developer/Xcode/UserData/Provisioning Profiles for the Xcode-generated profile. You can use QuickLook to inspect the profile. If you added the DriverKit USB (development) Capability, your profile should have idVendor='*'. This wildcard value will only work for development builds. Your entitlements.plist should have an entry called com.apple.developer.driverkit.transport.usb or "DriverKit USB Transport' which is an array, containing one or more items, each of which is a dictionary. Each dictionary should have an item with key idVendor and value a decimal number equal to the vendor ID of the device you're driving.

Well, welcome. Most Apple documentation is a reference of API calls, generated from header files. It tells you how to spell them, what the parameters are, sometimes what those parameters mean, what OS versions you can use them in, and not much else. Learning from these resources is like trying to learn a natural language from a dictionary. Apple has some videos from WWDC presentations about new technologies, but these tend to assume familiarity with the language and the problem domain. In the olden days (maybe twenty years ago), I might have said "get a book", but books are out of date the moment they are written. If you have access to an AI, I can recommend this approach. Prompt it with a program you have written in Python. Tell it that you are a Python programmer, and you are new to Swift, and that it should translate the program to Swift, and explain what it does and how the code compares to the Python implementation. Ask it to provide links to relevant documentation. Then read the explanation it provides, follow the links, read those. Try out the code (remember, AI makes mistakes, confidently). There are also a lot of good resources on the web. If you're stuck with how to use a particular API, search for " example". Pretty soon you'll identify some sites you will want to return to again and again. Good luck!

We parse the locationID out of the AVCaptureDevice.uniqueID and then find the IORegistry node with that locationID. Is there's a document declares how AVFoundation generate the unique_id for USB camera, no so I can assume this convert will always work? you can't Or is there's a way to send a PTZ control request to AVCaptureDevice? not that I know of. As far as I know, the only way is what you're doing. It looks that the unique_id provided is (locationID<<32|VendorID<<16|ProductID) as hex string, but I'm not sure if I can always assume this behavior won't change. Correct - it has changed in the past, it might change at any time in the future. Not all AVCaptureDevices are UVC, but they all have uniqueIDs. If you would like an API to clearly identify an AVCapture device in the IORegistry, please file a bug. I already did (in 2019, FB6146541)

are you using IOServiceGetMatchingService("DriverKitAcxxx") as shorthand for let dict = IOServiceNameMatching("DriverKitAcxxx") service = IOServiceGetMatchingService(kIOMainPortDefault, dict) and did you call RegisterService from your driver code?

Just to let you know, FB19449747 has been fixed, so there is now a development-only entitlement for PCI DriverKit. I was asked to follow up on FB19449747 after this was supposedly fixed, so I did. I can't see a DriverKit PCI Transport (development) entitlement in the list of available Capabilities.

Hi David you can use the Feedback Assistant app on macOS, or https://feedbackassistant.apple.com to log a trackable bug, which you can assign to your self or your development team (if you are a member of one). That other link seems to be for anonymous user feedback.

are you developing for macOS or iPadOS, or both? com.apple.developer.driverkit.communicates-with-drivers is for iPadOS. It won't do any harm to set this to true in a macOS app, but you don't need it. When you say your driver "fails at runtime", there are various ways this can occur: it fails to load (perhaps due to an entitlement issue), your code fails to find the driver your code finds the driver, but fails to open a user client for it It sounds like you're failing at stage 2. Look in the system log for messages related to your driver's bundle ID. I like to plug in the device, then run log collect --last 1m and peruse the resulting log file in the Console app. Use IORegistryExplorer (part of the additional tools for Xcode) to look for your driver in the IORegistry. If it isn't there, IOServiceGetMatchingService won't find it. IOServiceGetMatchingService takes a matching dictionary as a parameter, but you said you are calling IOServiceGetMatchingService("DriverKitAcxxx") Did you mean IOServiceNameMatching, or IOServiceGetMatchingService and you are passing in a dictionary created with CreateNameMatchingDictionary? Or something else? If you're using a matching dictionary, compare its contents carefully with the properties of your driver. Not that the name of the service is not a property called "name" (or at least, IORegistryExplorer doesn't display it as such). I like to use IOServiceNameMatching with a unique name (i.e. in your case I'd choose "com.accusys.Acxxx.driver"). Then, in your driver's Start_Impl, before you call RegisterService, call SetName("com.accusys.Acxxx.driver"). This enables you to write a generic name for your driver's class like "driver", while having a unique name to look for the in IORegistry.

most of the information you're looking for is in the support article you linked to. You probably want to scroll down this page and follow the directions to apply to the MFi program. https://mfi.apple.com

go to ~/Library/Developer/Xcode/UserData/Provisioning Profiles and use QuickLook to inspect the Xcode-generated .provisionprofile file for your app, to be sure that its com.apple.developer.driverkit.userclient-access claim is correct. in the meantime, you could set com.apple.developer.driverkit.allow-any-userclient-access to true in your driver.