Support for Apple Silicon Macs (M1/M2/M3)

.gitignore

@@ -1,3 +1,4 @@
 /target
 **/*.rs.bk
 Cargo.lock
+rust-toolchain

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ddc-macos"
-version = "0.3.0"
+version = "0.2.2"
 authors = ["Haim Gelfenbeyn <haim@g8n.me>"]
 description = "DDC/CI monitor control on MacOS"
 documentation = "https://haimgel.github.io/ddc-macos-rs/ddc_macos"
@@ -12,13 +12,14 @@ categories = ["hardware-support", "os::macos-apis"]
 edition = "2021"
 
 [dependencies]
-core-foundation = "0.10.0"
+core-foundation = "0.10"
 core-foundation-sys = "0.8"
 core-graphics = "0.24"
-ddc = "0.3"
+# ddc must stay on "0.2" till ddc-hi is also updated
+ddc = "0.2"
 io-kit-sys = "0.4"
-mach = "0.3"
-thiserror = "1"
+mach2 = "0.4"
+thiserror = "1.0"
 
 [dev-dependencies]
 edid-rs = "0.1"

rustfmt.toml

@@ -1,3 +1,3 @@
 max_width = 120
-edition = "2021"
+style_edition = "2021"
 use_try_shorthand = true

src/arm.rs

@@ -0,0 +1,175 @@
+use crate::error::Error;
+use crate::error::Error::{DisplayLocationNotFound, ServiceNotFound};
+use crate::iokit::IoIterator;
+use crate::iokit::{CoreDisplay_DisplayCreateInfoDictionary, IoObject};
+use crate::{kern_try, verify_io};
+use core_foundation::base::{CFType, TCFType};
+use core_foundation::dictionary::CFDictionary;
+use core_foundation::string::CFString;
+use core_foundation_sys::base::{kCFAllocatorDefault, CFAllocatorRef, CFTypeRef, OSStatus};
+use core_graphics::display::CGDisplay;
+use ddc::{I2C_ADDRESS_DDC_CI, SUB_ADDRESS_DDC_CI};
+use io_kit_sys::keys::kIOServicePlane;
+use io_kit_sys::types::{io_object_t, io_registry_entry_t};
+use io_kit_sys::{
+    kIORegistryIterateRecursively, IORegistryEntryCreateCFProperty, IORegistryEntryGetName,
+    IORegistryEntryGetParentEntry, IORegistryEntryGetPath,
+};
+use mach2::kern_return::KERN_SUCCESS;
+use std::ffi::CStr;
+use std::os::raw::{c_uint, c_void};
+use std::time::Duration;
+
+pub type IOAVService = CFTypeRef;
+
+pub(crate) fn execute<'a>(
+    service: &IOAVService,
+    i2c_address: u16,
+    request_data: &[u8],
+    out: &'a mut [u8],
+    response_delay: Duration,
+) -> Result<&'a mut [u8], crate::error::Error> {
+    unsafe {
+        verify_io(IOAVServiceWriteI2C(
+            *service,
+            i2c_address as _, // I2C_ADDRESS_DDC_CI as u32,
+            SUB_ADDRESS_DDC_CI as _,
+            // Skip the first byte, which is the I2C address, which this API does not need
+            request_data[1..].as_ptr() as _,
+            (request_data.len() - 1) as _, // command_length as u32 + 3,
+        ))?;
+    };
+    if !out.is_empty() {
+        std::thread::sleep(response_delay);
+        unsafe {
+            verify_io(IOAVServiceReadI2C(
+                *service,
+                i2c_address as _, // I2C_ADDRESS_DDC_CI as u32,
+                0,
+                out.as_ptr() as _,
+                out.len() as u32,
+            ))?;
+        };
+        Ok(out)
+    } else {
+        Ok(&mut [0u8; 0])
+    }
+}
+
+/// Returns an AVService and its DDC I2C address for a given display
+pub(crate) fn get_display_av_service(display: CGDisplay) -> Result<(IOAVService, u16), Error> {
+    if display.is_builtin() {
+        return Err(ServiceNotFound);
+    }
+    let display_infos: CFDictionary<CFString, CFType> =
+        unsafe { CFDictionary::wrap_under_create_rule(CoreDisplay_DisplayCreateInfoDictionary(display.id)) };
+    let location = display_infos
+        .find(CFString::from_static_string("IODisplayLocation"))
+        .ok_or(DisplayLocationNotFound)?
+        .downcast::<CFString>()
+        .ok_or(DisplayLocationNotFound)?
+        .to_string();
+    let external_location = CFString::from_static_string("External").into_CFType();
+
+    let mut iter = IoIterator::root()?;
+    while let Some(service) = iter.next() {
+        if let Ok(registry_location) = get_service_registry_entry_path((&service).into()) {
+            if registry_location == location {
+                while let Some(service) = iter.next() {
+                    if get_service_registry_entry_name((&service).into())? == "DCPAVServiceProxy" {
+                        let av_service = unsafe { IOAVServiceCreateWithService(kCFAllocatorDefault, (&service).into()) };
+                        let loc_ref = unsafe {
+                            IORegistryEntryCreateCFProperty(
+                                (&service).into(),
+                                CFString::from_static_string("Location").as_concrete_TypeRef(),
+                                kCFAllocatorDefault,
+                                kIORegistryIterateRecursively,
+                            )
+                        };
+                        if !loc_ref.is_null() {
+                            let loc_ref = unsafe { CFType::wrap_under_create_rule(loc_ref) };
+                            if !av_service.is_null() && (loc_ref == external_location) {
+                                return Ok((av_service, i2c_address(service)));
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    Err(ServiceNotFound)
+}
+
+const I2C_ADDRESS_DDC_CI_MDCP29XX: u16 = 0xB7;
+
+/// Returns the I2C chip address for a given service
+fn i2c_address(service: IoObject) -> u16 {
+    // M1 Macs use a non-standard chip address on their builtin HDMI ports: they are behind a
+    // MDCP29xx DisplayPort to HDMI bridge chip, and it needs a different I2C slave address:
+    // not a standard 0x37 but 0xB7.
+    let mut parent: io_registry_entry_t = 0;
+    unsafe {
+        if IORegistryEntryGetParentEntry((&service).into(), kIOServicePlane, &mut parent) != KERN_SUCCESS {
+            return I2C_ADDRESS_DDC_CI;
+        }
+    }
+    let class_ref = unsafe {
+        IORegistryEntryCreateCFProperty(
+            parent,
+            CFString::from_static_string("EPICProviderClass").as_concrete_TypeRef(),
+            kCFAllocatorDefault,
+            kIORegistryIterateRecursively,
+        )
+    };
+    if class_ref.is_null() {
+        return I2C_ADDRESS_DDC_CI;
+    }
+    let mcdp29xx = CFString::from_static_string("AppleDCPMCDP29XX").into_CFType();
+    let class_ref = unsafe { CFType::wrap_under_create_rule(class_ref) };
+    if class_ref == mcdp29xx {
+        I2C_ADDRESS_DDC_CI_MDCP29XX
+    } else {
+        I2C_ADDRESS_DDC_CI
+    }
+}
+
+fn get_service_registry_entry_path(entry: io_registry_entry_t) -> Result<String, Error> {
+    let mut path_buffer = [0_i8; 1024];
+    unsafe {
+        kern_try!(IORegistryEntryGetPath(entry, kIOServicePlane, path_buffer.as_mut_ptr()));
+        Ok(CStr::from_ptr(path_buffer.as_ptr()).to_string_lossy().into_owned())
+    }
+}
+
+fn get_service_registry_entry_name(entry: io_registry_entry_t) -> Result<String, Error> {
+    let mut name = [0; 128];
+    unsafe {
+        kern_try!(IORegistryEntryGetName(entry, name.as_mut_ptr()));
+        Ok(CStr::from_ptr(name.as_ptr()).to_string_lossy().into_owned())
+    }
+}
+
+#[link(name = "CoreDisplay", kind = "framework")]
+extern "C" {
+    // Creates an IOAVService from an existing I/O Kit service
+    fn IOAVServiceCreateWithService(allocator: CFAllocatorRef, service: io_object_t) -> IOAVService;
+
+    // Reads data over I2C from the specified IOAVService
+    fn IOAVServiceReadI2C(
+        service: IOAVService,
+        chip_address: c_uint,
+        offset: c_uint,
+        output_buffer: *mut c_void,
+        output_buffer_size: c_uint,
+    ) -> OSStatus;
+
+    // Writes data over I2C to the specified IOAVService
+    fn IOAVServiceWriteI2C(
+        service: IOAVService,
+        chip_address: c_uint,
+        data_address: c_uint,
+        input_buffer: *const c_void,
+        input_buffer_size: c_uint,
+    ) -> OSStatus;
+}
+

src/error.rs

@@ -0,0 +1,51 @@
+use core_graphics::base::CGError;
+use ddc::ErrorCode;
+use io_kit_sys::ret::kIOReturnSuccess;
+use mach2::kern_return::{kern_return_t, KERN_FAILURE};
+use thiserror::Error;
+
+/// An error that can occur during DDC/CI communication with a monitor
+#[derive(Error, Debug)]
+pub enum Error {
+    /// Core Graphics errors
+    #[error("Core Graphics error: {0}")]
+    CoreGraphics(CGError),
+    /// Kernel I/O errors
+    #[error("MacOS kernel I/O error: {0}")]
+    Io(kern_return_t),
+    /// DDC/CI errors
+    #[error("DDC/CI error: {0}")]
+    Ddc(ErrorCode),
+    /// Service not found
+    #[error("Service not found")]
+    ServiceNotFound,
+    /// Display location not found
+    #[error("Display location not found")]
+    DisplayLocationNotFound,
+}
+
+pub fn verify_io(result: kern_return_t) -> Result<(), Error> {
+    if result == kIOReturnSuccess {
+        Ok(())
+    } else {
+        Err(Error::Io(result))
+    }
+}
+
+impl From<std::io::Error> for Error {
+    fn from(error: std::io::Error) -> Self {
+        Error::Io(error.raw_os_error().unwrap_or(KERN_FAILURE))
+    }
+}
+
+impl From<ErrorCode> for Error {
+    fn from(error: ErrorCode) -> Self {
+        Error::Ddc(error)
+    }
+}
+
+impl From<CGError> for Error {
+    fn from(error: CGError) -> Self {
+        Error::CoreGraphics(error)
+    }
+}