Why can the driverkit be successfully loaded, but the init and start functions are not executed？（sometimes it works sometimes it doesn't）

Hi. I have a class-compliant usb device which announces its serial number as m4121095, as per its kUSBSerialNumberString property. However, the file name it is provided is tty.usbmodemm41210951 – it's the serial number with an additional 1 at the end. What is the meaning of this appendage? (I'm tempted to believe that the 1 at the end is there in the unlikely case another device with the same SN is connected, but there's no way to test this possibility). In the end, I would like to obtain a filename that is guaranteed to be representing a connection to exactly this device. Can I assume that the filename of a device that follows the same protocol of serial numbering will be consistently appended with a number that can in some way be inferred? Thank you.

I have a regular GUI-based app that communicates with an Endpoint System Extension installed by another app. Both the GUI app and Endpoint System Extension have the same Team ID and are part of the same App Groups. But I still need to do one of the following to the GUI-based app to allow it to communicate with the Endpoint System Extension over XPC: Disable the sandbox Add com.apple.security.temporary-exception.mach-lookup.global-name to entitlements For some reason I thought there was another way to resolve this. Am I missing anything? (My goal is to allow an app distributed through the Mac App Store to communicate with my Endpoint System Extension if it exists, and I am worried about the "temporary-exception" entitlement needed to support this.)

My mac os 13.4 do not have PICDriverKit.framework, so I can not build pci driverkit, is that normal?

Why can't Mac os 13.4 or xcode 14.3 build driverkit sign to run locally from xcode？

Hi everyone, I am fairly new to Apple development. I have been working on a project where I need Mac to interface with an HID device (custom device). I have successfully communicated with the device using IOKit, Core Foundation and Driver Kit frameworks by simply importing these frameworks in the project and making use of their APIs. However, my client is now asking that I develop the communication explicitly using HID Driver Kit. Bear in mind that I have not purchased the apple developer certificate nor do I have any provisional signing certificates and without any of these, Xcode was allowing me to use frameworks like IOKit, DriverKit etc. Now, when I tried importing HIDDriverKit into the project, I am not able to find this framework in the "Frameworks and Libraries" tab. How do I import this framework into my project? Do I have to purchase apple developer ID or get the provisional signing certificates or any other formalities are required? Please let me know what can be done. Any pointers or suggestions are welcome. Best, Vishnu

I ran into a strange problem during development this morning. When trying to install my Endpoint and Network System Extensions (something I was able to do yesterday, and many times before), my Mac is prompting me to enable Kernel Extensions. Right before this happened, I had problems deleting the previous version of the apps from the /Applications folder (it took many tries). This too was unusual. After agreeing to allow the installation of my Endpoint System Extension, I was greeted with this previously unseen message and button: When I click "Enable System Extensions...", and I am greeted with this alert: I also ran into this problem when trying to install my Network System Extension. Anyone have any idea how I screwed up my system? Anyone know how to return it to normal behavior? System: Mac Studio 2022 OS: Ventura 13.4.1 (I'm thinking of re-instaling Ventura this evening; would prefer not to)

Hello, I am trying to run a sample project from Apple's Developer Documentation that creates and interfaces with a DriverKit Dext. The project can be found here: Creating an Audio Device Driver. I have followed all the steps in the README.md file: downloading the code, enabling automatic signing, building the app, moving it to the Applications folder, and launching it. I then open the app, press "Install Dext", enable it through System Preferences, and receive the message "SoundboardDriver has been activated and is ready to use." However, the audio device does not appear in the MIDI app, there is no mention of it in the IORegistry, and I get the message “Driver extension is not running” when I try to press "Open User Client". Is there another step I need to follow to get the app running? Perhaps it's an entitlement issue? I don't see any error/fault message in the console app relating to the app or driver. I am running MacOS 13.4.1 (22F82) and Xcode 14.3.1 (14E300c). I have tried with and without SIP enabled, but the issue persists. Any help or guidance would be greatly appreciated. Best, Henry

Hi All, Is there a limit on the data size of input and output in IOConnectCallStructMethod? I am working with CommunicatingBetweenADriverKitExtensionAndAClientApp. It seems there a buffer size limit in OversizedDataStruct in the sample code. typedef struct { uint64_t foo; uint64_t bar; uint64_t largeArray[511]; } OversizedDataStruct; If I tested by changing 511 to 0x1E00000(30MB), I got below error. Thread 1: EXC_BAD_ACCESS (code=2, address=0x16f20fff8) I need to get large image data(over 30 MBytes) from driver(dext) to user client application. How can I transfer more than 30MB of data from driver to App with IOConnectCallStructMethod? Or is there any other way without using IOConnectCallStructMethod? Please help.

IOPSCopyPowerSourcesInfo → kIOPSBatteryHealthKey returning incorrect value Background: I write software to monitor computer system health. I'm having problems getting battery health information on my new M2 notebook. Given the following Objective-C program: #include <Foundation/NSObjCRuntime.h> #include <IOKit/ps/IOPSKeys.h> #include <IOKit/ps/IOPowerSources.h> #include <assert.h> int main() { CFTypeRef psInfo = IOPSCopyPowerSourcesInfo(); assert(psInfo != NULL); CFArrayRef list = IOPSCopyPowerSourcesList(psInfo); assert(list != NULL); long count = CFArrayGetCount(list); for(long i = 0; i < count; i++) { CFDictionaryRef ps = IOPSGetPowerSourceDescription( psInfo, CFArrayGetValueAtIndex(list, i)); assert(ps != NULL); CFStringRef deviceName = (CFStringRef)CFDictionaryGetValue( ps, CFSTR(kIOPSNameKey)); assert(deviceName != NULL); CFStringRef serialNumber = (CFStringRef)CFDictionaryGetValue( ps, CFSTR(kIOPSHardwareSerialNumberKey)); assert(serialNumber != NULL); CFStringRef health = (CFStringRef)CFDictionaryGetValue( ps, CFSTR(kIOPSBatteryHealthKey)); assert(health != NULL); NSLog(@"\nName=\"%@\"\nSerialNumber=\"%@\"\n" "BatteryHealth=\"%@\"\n", (__bridge NSString*)deviceName, (__bridge NSString*)serialNumber, (__bridge NSString*)health); } CFRelease(list); CFRelease(psInfo); return 0; } and looking at the IOPSKeys.h header, I expect to get one of "Poor", "Fair", or "Good" for the value of kIOPSBatteryHealthKey. https://opensource.apple.com/source/IOKitUser/IOKitUser-1845.81.1/ps.subproj/IOPSKeys.h.auto.html Instead, on my 2022 M2 Macbook Air running 13.2.1 (22D68), I get the following output: Name="InternalBattery-0" SerialNumber="F8Y2422145S10X2A7" BatteryHealth="Check Battery" At the same time, the "System Information app says "Condition: Normal". Am I missing something? This seems to be a bug, right? Should I look into filing a Technical Support Incident?

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

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.

hi, so i have a little bit of work left on the Asus Xonar family of audio devices. thanks to APPUL's samplepciaudiodriver code and their excellent documentation, Evegeny Gavrilov's kxAudio driver for MAC and Takashi Iwai's exceptional documentation of the ALSA API i have something that is ready for testing. the stats look good, but unfortunately i this is my second HDAV1.3 deluxe. the other one is also in the same room consuming all of my devices with powered audio outputs. no matter, i am in the process of acquiring another xonar sound card in this family. which brings me to my question: what is the benefit of getting an apple developer account for 99 dollars a year? will i be able to distribute a beta kext with my signature that will allow people to test the binary? i don't think others could run a self-signed kext built on one machine, on another, correct? so would a developer license allow others to test a binary built on my machine, assuming they're x86? my hope is that the developer program would allow me to test the binaries and solicit input from enthusiast mac pro owners WORLD WIDE. i them hope to create a new program that will give us the wealth mixers/controls this fantastic line is capable of providing.

I can't find any useful help about the content described in the title on Apple's official website. The relevant help on its official website is almost all based on OC language, and even their sample programs are written in OC language. Can I ask if SWIFT can only use the COM port through the bridge of OC-SWIFT?

As i read Driverkit can be used to write the device driver. But, I want to filter a device. can Driverkit be used for filtering a particular device?

The "deployment target" for a DEXT is a number like 19.0 or 21.4. Xcode seems to pick the latest version on the machine you are creating the target on as a default - so if I make a new Driver target on Xcode 14 and Ventura, the Deployment Target for the driver will be 21.4. If I'm targeting macOS 12 (for example), what version of DriverKit should I choose, and where is this documented?

I'm trying to built a USBDriverKit driver on the Mac. The driver loads properly but when my device is inserted the driver is ignored and instead the com.apple.AppleUserHIDDrivers driver is loaded. I do not understand what is causing this. The device both have USB and HID cababilities but I want it to work with USBDriverKit so that the driver can be used on the Ipad as well. How can I get the driver to match properly? Entitlements: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>com.apple.developer.driverkit</key> <true/> <key>com.apple.developer.driverkit.transport.usb</key> <array> <dict> <key>idVendor</key> <integer>1240</integer> </dict> </array> <key>com.apple.developer.driverkit.userclient-access</key> <true/> <key>com.apple.security.app-sandbox</key> <true/> </dict> </plist> Info.plist: ... <dict> <key>CFBundleIdentifier</key> <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string> <key>IOKitPersonalities</key> <dict> <key>ClickerDriver</key> <dict> <key>IOKitDebug</key> <string>65535</string> <key>CFBundleIdentifier</key> <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string> <key>IOClass</key> <string>IOUserService</string> <key>IOProviderClass</key> <string>IOUSBHostInterface</string> <key>IOUserClass</key> <string>ClickerDriver</string> <key>IOUserServerName</key> <string>example.Clicker.driver</string> <key>bInterfaceClass</key> <string>3</string> <key>bInterfaceSubClass</key> <string>0</string> <key>bConfigurationValue</key> <string>1</string> <key>bInterfaceNumber</key> <string>0</string> <key>idProduct</key> <integer>63</integer> <key>idVendor</key> <integer>1240</integer> <key>UserClientProperties</key> <dict> <key>IOClass</key> <string>IOUserUserClient</string> <key>IOUserClass</key> <string>ClickerDriverUserClient</string> </dict> </dict> </dict> <key>OSBundleUsageDescription</key> <string>The app interprets monitors key presses. </string> </dict> </plist> Output of ioreg -b -n "Simple HID Device Demo" -r -l is attacheded. ioreg.log

We are developing driver for our USB device. Our approach is to run and test driver on macOS first and then verify on iPadOS 16. In the driver we add custom property -"kUSBSerialNumberString" into default properties: OSDictionary * Driver::devicePropertiesWithSerialNumber() {     kern_return_t ret;     OSDictionary *properties = NULL;     OSDictionary *dictionary = NULL;     OSObjectPtr value;     const IOUSBDeviceDescriptor *deviceDescriptor;     deviceDescriptor = ivars->device->CopyDeviceDescriptor();          ret = CopyProperties(&properties);     value = copyStringAtIndex(deviceDescriptor->iSerialNumber, kIOUSBLanguageIDEnglishUS);     Log("Serial number: %{public}s", ((OSString *)value)->getCStringNoCopy());          dictionary = OSDictionary::withDictionary(properties, 0);     OSSafeReleaseNULL(properties);     if (value) {         OSDictionarySetValue(dictionary, "kUSBSerialNumberString", value);         OSSafeReleaseNULL(value);     }     return  dictionary; } next in kern_return_t IMPL(Driver, Start) we call SetProperties:     ret = SetProperties(devicePropertiesWithSerialNumber());     if(ret != kIOReturnSuccess) {         Log("Start() - Failed to set properties: 0x%08x.", ret);         goto Exit;     } We can read our property on macOS using:     func getDeviceProperty(device: io_object_t, key: String) -> AnyObject? {         IORegistryEntryCreateCFProperty(             device, key as CFString, kCFAllocatorDefault, .zero         )?.takeRetainedValue()     }         if let serialNumber = getDeviceProperty(device: driver, key: "kUSBSerialNumberString") {             print("serialNumber: \(serialNumber)")         } However getDevicePropertyon iPadOS returns nil. We are wondering is any limitation for IORegistry entries(properties) on iPadOS16? Is any way to add custom property to IORegistry? BTW, we added debug method to print all the available properties for IORegistry:     private func debugRegistry(device: io_object_t) {         var dictionary: Unmanaged<CFMutableDictionary>?         IORegistryEntryCreateCFProperties(device, &dictionary, kCFAllocatorDefault, .zero)         if let dictionary = dictionary {             let values = dictionary.takeUnretainedValue()             print(values)         }     } It returns just 1 property for iPadOS: { IOClass = IOUserService; } and much more for macOS including our custom one: { CFBundleIdentifier = "****"; CFBundleIdentifierKernel = "com.apple.kpi.iokit"; IOClass = IOUserService; IOMatchCategory = "***"; IOMatchedPersonality = { CFBundleIdentifier = "****"; CFBundleIdentifierKernel = "com.apple.kpi.iokit"; IOClass = IOUserService; IOMatchCategory = "****"; IOPersonalityPublisher = "****"; IOProviderClass = IOUSBHostInterface; IOResourceMatch = IOKit; IOUserClass = Driver; IOUserServerCDHash = 9cfd03b5c1b90da709ffb1455a053c5d7cdf47ac; IOUserServerName = "*****"; UserClientProperties = { IOClass = IOUserUserClient; IOUserClass = DriverUserClient; }; bConfigurationValue = 1; bInterfaceNumber = 1; bcdDevice = 512; idProduct = XXXXX; idVendor = XXXXX; }; IOPersonalityPublisher = "*****"; IOPowerManagement = { CapabilityFlags = 2; CurrentPowerState = 2; MaxPowerState = 2; }; IOProbeScore = 100000; IOProviderClass = IOUSBHostInterface; IOResourceMatch = IOKit; IOUserClass = Driver; IOUserServerCDHash = 9cfd03b5c1b90da709ffb1455a053c5d7cdf47ac; IOUserServerName = "*****"; UserClientProperties = { IOClass = IOUserUserClient; IOUserClass = DriverUserClient; }; bConfigurationValue = 1; bInterfaceNumber = 1; bcdDevice = 512; idProduct = XXXXX; idVendor = XXXXXX; kUSBSerialNumberString = XXXXXXXXXXX; }

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!

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?