Random reboot error: Panic "No device added after powering on the rails"

Aris1978 wrote:

If it's out of warranty, and this is a known hardware issue, shouldn't Apple still fix at no cost?

It is a known issue here on the forums, but Apple doesn't participate here in the forums. The only way Apple will take notice is if people create a numbered support case with Apple support and the issue must be escalated to the Apple engineers to investigate. Very few people seem to do this. Apple cannot fix or address a problem if they don't know about it or have insufficient information & details from people affected by the problem....assuming it is a problem that Apple can even address.....it could be a problem the user and/or the manufacturer of third party hardware you are using will need to address. But first you need to identify the exact hardware & conditions which are triggering this problem.

Plus, like I posted previously, some of these issues are user related & localized due to other connected devices or using bad, incompatible, or insufficient quality cables & devices. Users need to go through their own troubleshooting to narrow down the issue which may require working with Apple support directly....it may take time the troubleshooting.

I really cannot say what is the cause of this problem since I have only seen a couple of posts where people actually did more extensive testing & troubleshooting & report back on what fixed their issue. Likely each user may have a slightly different item causing the problem.

Read and follow the steps described in If your Mac restarts and a message appears - Apple Support.

What that Apple Support document fails to state is that most KP events are caused by faulty hardware, and that if you reach the end of all those steps the final recommendation is to contact Apple to have that Mac evaluated.

Use this link: Official Apple Support

The DCP in AppleDCPDPTXPowerController refers to the Display Coprocessor, and the KP is reporting that it did not respond after power became available to it. There are a number of possible reasons for that including a faulty display angle sensor (tells the Mac its lid is open), a faulty display assembly, or similar hardware-specific cause. Workarounds allegedly exist that I won't go into because they don't change the fact this is a hardware problem that Apple needs to fix.

Don't let them ignore you.

I've seen reports on this forum where users found externally connected devices can cause this problem due to compatibility issues....sometimes from even using the wrong or low end cables to connect a display or other device.

@John Galt is correct, it is a hardware issue of some sort, but it could be a hardware issue with an external device such as a cable or external display, or something that has display technology built into it such as dock or hub. Or perhaps using an incompatible display resolution or refresh rate for the external display. It may not be a Mac hardware issue, although that is a possibility as well.

You will probably need to do some troubleshooting & experimentation to figure it out. Or you will need to generate a tech support case with Apple which may need to be escalated to an engineer at some point. Apple will always start out with very basic troubleshooting steps, so it will take time unless the issue occurs without any external devices connected and it occurs with a clean install of macOS without any third party apps installed and without restoring the system from a backup......if it occurs under those conditions, then Apple will begin replacing parts to resolve the issue, otherwise.....you are probably in for some long troubleshooting until you discover the culprit.

Is the Mac in question an M2 MacBook Air?

Identify your MacBook Air model - Apple Support

If it's out of warranty, and this is a known hardware issue, shouldn't Apple still fix at no cost?