https://bugs.freedesktop.org/show_bug.cgi?id=110217

Bug ID: 110217 Summary: RX580: screen turns black or flickers until forced reconfiguration Product: DRI Version: unspecified Hardware: x86-64 (AMD64) OS: Linux (All) Status: NEW Severity: normal Priority: medium Component: DRM/AMDgpu Assignee: dri-devel@lists.freedesktop.org Reporter: numzer0@yandex.ru

Created attachment 143754 --> https://bugs.freedesktop.org/attachment.cgi?id=143754&action=edit dmesg output

I have a Radeon RX560 and VGA monitor (with broken EDID) connected via a cheap HDMI-to-VGA converter (with its own broken EDID).

The system starts up normally. During boot up, it should change display resolution as specified in the kernel command line (`video=1280x1024-32@75`, monitor native). Screen turns black instead, and resolution remains unchanged. But after I plug HDMI out and in, the monitor gets new resolution and shows console login prompt, as expected. (X isn’t configured to start at bootup).

Then, when I `startx`, it chooses the same resolution but wrong frequency (85 Hz, too much for my monitor). That’s probably due to converter supplying the EDID. After I run `xrandr --rate 75`, it switches to the correct mode.

I wouldn’t even mention such small nuisance, but if I specify exactly the same mode (as reported by `xrandr --verbose`) explicitly (as a `Modeline`), it works but flickers, despite the `TearFree` option enabled. Moreover, when the monitor is turned off and then on, it wakes up in the same mode *but flickers.* Changing mode back and forth (`xrandr --output HDMI-A-0 --preferred ; xrandr --rate 75`) helps.

I usually have `compton` running. Without it, flicker is tolerable but still present.

OS: Arch Linux Kernel: Linux 5.0.1-arch1-1-ARCH X driver: xf86-video-amdgpu 19.0.0-1