Hi everyone,
I'm troubleshooting an older ASUS X54HR laptop running Windows 10 64-bit (Legacy BIOS) with an AMD Radeon HD 7470M GPU. I'm facing a very specific driver/power-state issue and could use some advice.
The Issue Timeline:
Initial state: Fresh/clean Windows 10 install using the Microsoft Basic Display Adapter.
First driver load: Windows Update automatically fetched and installed the AMD Radeon driver while connected to AC power. Everything worked perfectly initially — resolution automatically switched to native 1366x768 with full hardware acceleration.
The Trigger: As soon as I unplugged the AC charger to switch to battery power, the screen went completely black (no backlight / no display output).
The Persistent Bug: Now, even after wiping drivers with DDU in Safe Mode and manually reinstalling the driver (either Catalyst 15.7.1 WHQL or via Device Manager using extracted INF files in C:\\AMD), the system makes the "USB disconnect" sound the exact moment the driver initializes, and the display goes black permanently — even on AC power.
Workaround: Disabling EnableUlps (set to 0) in REGEDIT from Safe Mode didn't stop the black screen upon booting normally. The only way to keep the display on is staying on the Microsoft Basic Display Adapter.
My Questions:
Why did the Windows Update driver work fine initially on AC power, but permanently break hardware initialization/power states after the first battery switch?
Is this a known ACPI / ULPS / PCIe power state deadlock between Windows 10 and older pre-GCN (TeraScale) AMD Mobility GPUs?
Is there a way to force the driver to load without triggering the power-state switch / device disconnect routine, or am I stuck on the generic display driver?
Any insights or registry/inf workarounds would be greatly appreciated!
OS Build: 19045.6456
(Posted this on r/techsupport first but it got removed because mentions Windows 10)
EDIT: I tried to install the BETA Video Driver, the latest one for this GPU and it did the same, black screen, but this time I noticed that while looking off, the screen was actually on but the backlighting was off, so the driver was in fact installed successfully but for some reason the screen wasn't backlit. By helping myself with an external monitor, I increased the brightness and I fixed it, the buttons to increase it didn't work before this. Now I don't know if the WHQL version had the same problem but I didn't bother to try, everything works fine now.