Help disabling temporal dithering

[caboy]

Hey folks,
Any chance the Intel folks might be able to help with this? I am looking for a way to disable temporal dithering on an Intel Iris XE built-in GPU. I think I am fairly close to a possible answer.

I get really bad eye pain / strain from some displays. From what I understand temporal dithering or PWM (pulse width modulation) seem to be the culprits. Both have a rapid flicker that my (and fellow sufferers) eyes try to adjust to 60(?) times per second, which leads to severe pain.

There is a video here that explains what is happening with our eyes and why it causes pain: https://www.youtube.com/watch?v=Ovs0p3jJJt4

What I am asking for help with:

I believe I am close to finding a way to disable temporal dithering. I need help from the Intel folks on which register poke at and what value to set it to.

I have a Dell XPS 13 9305 with an Intel IRIS XE GPU. When I first bought the computer, it was good. No issues. It had Windows 10 21H2. I installed Fedora 34 and that was fine also.

At some point the Microsoft auto updates must have updated the GPU driver and I started getting really bad eye pain from the display.  I noticed immediate pain when rebooting to Windows one day.  Even when rebooting into Linux the eye pain persisted.

I restored from a disk image to my factory Win10 OS install and the problem went away (auto updates are now disabled). The Linux side is good again too.

The fact that the issue is present or lacking for both Windows and Linux depending on which patch level Windows is at leads me to believe there is a GPU register being set by the Windows driver.

There used to be a Windows program that could disable temporal dithering on Intel IRIS GPUs called "Ditherig". It seems that program no longer works, and from what I have read the author has not replied to emails for about 2 years.

I have another nearly identical computer for testing (XPS 13 9305). That one is Windows 11 / Fedora. That one gives me eye pain as it is.

I dumped the GPU register values from both computers (using Linux "intel_reg" utility) and made a diff. There are a lot of values that are different between the two computers and I do not know what registers might be the right ones to poke at, or what values to set them to.

I was not able to find any documentation online about Intel GPU registers or values. Any chance I could get some guidance from the Intel folks on this please? Which registers control temporal dithering and what values should they be set to to disable it?

I know C and have taken a class on Linux systems programming in C, so I can understand some tech stuff.

Thank you

[Hugo_Intel]

Hello caboy

Thank you for posting on the Intel Communities.

I understand you are looking to know how to disable dithering from the Intel driver in your graphics adapter, we know that dithering can sometimes cause eye issues and can be bothersome, however, disabling dithering is not possible and there are no settings to control the status. Taking into consideration that you are using a laptop our recommendation is that you contact the manufacturer as Dell might be able to provide more information at a hardware level.

Best Regards,

Hugo O.

Intel Customer Support Technician.

[Hugo_Intel]

Hello caboy

I see there are no further questions related to this topic so we will no longer monitor this thread. As mentioned in our previous post there are no settings to control dithering within the graphics driver, however, we recommend that you check with your system manufacturer as they might have a method or tool to control dithering. Feel free to open a new topic if you have further questions.

Best Regards,

Hugo O.

Intel Customer Support Technician.

[caboy]

  Hi Hugo,
Thank you for the reply.  I have tried asking the folks at Dell and not received a response. 

Are there any docs you can point me to that show what the registers and their settings are?

Thank you