@FireWolf8 months ago
Ice Lake Intel Iris Plus Graphics on macOS Catalina: A solution to the kernel panic due to unsupported core display clock frequencies in the framebuffer driver
Hi folks! I haven’t updated my blog for a long time, but today I have something new about the graphics driver for Ice Lake platforms on macOS Catalina 10.15.6 to share with you. It’s time to write a new blog post.
If this page looks strange due to font or layout issues, you could find a pretty-printed version at here.
It has been quite a while since Apple released the graphics driver for Intel Ice Lake platforms. While we expect that it should not be difficult to make the integrated graphics card on an Ice Lake-based laptop work under macOS Catalina, a large number of people has encountered a kernel panic due to an unsupported Core Display Clock frequency. Core Display Clock (
CDCLK) is one of the primary clocks used by the display engine to do its work. Apple’s graphics driver expects that the EFI firmware has already set the clock frequency to either 652.8 MHz or 648 MHz, but quite a few laptops set it to a much lower value (e.g. 172.8 MHz), and hence a kernel panic is triggered. In the following sections, I will focus on how the graphics driver verifies and configures the Core Display Clock and how we add support for these valid yet unsupported frequencies.