Screen flashes on Dell XPS series and some other Intel platforms

Screen flashes on Dell XPS series and some other Intel platforms

Symptoms: On Dell XPS series platform, and possibly some other platforms, the USB monitor flashes badly.

Initial Investigation : we found that the low power Intel CPU might put the memory controller into conditional self-refresh mode during S0, and cause the XHCI DMA memory retrieval latency. Attaching an external mouse immediately cure the problem. 

Solution: You could try one of the following approaches:
1) Attaching an external USB mouse to keep USB host controller in "alert" mode. When this is done, the host controller schedules USB traffic in a agile manner.

2) Starting from driver 2.0.31559.0 or above, a high-resolution timer is added to keep integrated memory controller out of self-refresh mode.

3). Invoke HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\intelppm, and change "Start" registry value from 3 to 4, and then reboot. This disables the Intel C state management. You need a reboot to let registry setting take effect.

We suggest the end user to adopt approach 1, since the mouse driver uses less relaxed polling interval (which is typically 10 ms), and uses less CPU power.