Gurm Wouldn't shock me. We know that the more control developers have over the GPU, the higher the likelihood that we will not be able to look at it - see Windows 10 and Composition Spaces.
JTL ryans No they don't. All Macbook's with dedicated GPU's have used a multiplexer chip where they have both the Intel and AMD/Nvidia graphics chips, and it switches which GPU is connected to the display when the GPU is switched by the operating system. I've written about this before, for example
ryans JTL Right so Macbook Pro 15" has discrete Radeon graphics and integrated Intel HD Graphics 630, but I believe there's an application for force discrete graphics to be used always (at the expense of more power and decreased battery life though)
ryans Has anyone tried using an external USB video card (e.g. something like https://www.amazon.com/StarTech-External-Monitor-Graphics-USB32HDE/dp/B00OD37KHG?th=1)? That should theoretically bypass Intel graphics, right?
randomboolean ryans Please ask @ensete because I think he/she tried external VGA on this post https://ledstrain.org/d/185-not-pwm-not-dither-not-blue-light-not-refresh-rate-what-s-next-to-check/8 .
JTL ryans That should theoretically bypass Intel graphics, right? Yes. It uses its own chipset. But external video cards are often low quality and tend to to cause other issues so I've mostly ignored them. Worth a try though
JTL ryans Yes there is, but newer OS X version support is iffy and I believe the dithering still happens with with the Radeon card. If you email me I can tell you some things I'd rather not post publicly yet.
ryans Does anyone know if MBP has an 8-bit display (e.g. dithering is not required for best image quality)?
JTL ryans Does anyone know if MBP has an 8-bit display (e.g. dithering is not required for best image quality)? As of 2015 MBP. No. The iMac Pro does 10-bit color depth by temporal dithering which implies it's an 8+2 bit display using FRC. I suspect some HP Zbook laptops might have a native 8-bit display but I'd like to see one in person to confirm.
ryans I heard of this thing "Panel Self-Refresh" has anyone tried disabling it? https://wiki.archlinux.org/index.php/Intel_graphics
JTL ryans No. But it should be enough to use a live USB and test said kernel parameter i915.enable_psr=0