[SOLVED] Framebuffer problem since kernel 4.8

[schwarzygesetzlos]

Since gentoo-sources-4.8.2 my box has problems reaching console. I get framebuffer output to the point where the kernel states fb: switching to radeondrmfb from simple. After that no further output is shown on screen. The machine seems to freece as I cannot login via sshd from another box.

Anything suspicious in my kernel .config?
http://pastebin.com/tDp17BBP

I played around with the FB options to use FB_EFI or FB_VESA instead of FB_SIMPLE but had not much success. With FB_VESA I got no console output at all, with FB_EF the last message shown is fb: switching to radeondrmfb from efifb. The .config was copied over from gentoo-sources-4.7.8, did a make oldconfig and did not activate any of the new options. The box is running fine with kernel 4.7.x-series.

# inxi -b
System: Host: supah Kernel: 4.7.8-gentoo x86_64 (64 bit) Desktop: MATE 1.14.1
Distro: Gentoo Base System release 2.2
Machine: Mobo: ASRock model: 970 Extreme4 Bios: American Megatrends v: P2.80 date: 08/05/2015
CPU: Quad core AMD FX-8320E Eight-Core (-HT-MCP-) speed/max: 1400/3600 MHz
Graphics: Card: Advanced Micro Devices [AMD/ATI] Curacao XT [Radeon R7 370 / R9 270X/370 OEM]
Display Server: X.org 1.18.4 drivers: ati,radeon tty size: 211x55 Advanced Data: N/A for root
Network: Card: Intel 82541PI Gigabit Ethernet Controller driver: e1000
Drives: HDD Total Size: 2128.4GB (22.0% used)
Info: Processes: 245 Uptime: 26 min Memory: 760.4/16054.2MB Client: Shell (bash) inxi: 2.3.0
_________________
Talos II. [Gentoo Linux] | PMac G5 11,2. PMac G4 3,6. PBook G4 5,8. [MorphOS 3.18 / Gentoo Linux / Adelie Linux] | A600GS [Amibench / Amiga OS 3.2.2.1]

[schwarzygesetzlos]

This thread pointed me to the solution.

Installing latest firmware helped:
emerge =sys-kernel/linux-firmware-20160628 ~amd64
_________________
Talos II. [Gentoo Linux] | PMac G5 11,2. PMac G4 3,6. PBook G4 5,8. [MorphOS 3.18 / Gentoo Linux / Adelie Linux] | A600GS [Amibench / Amiga OS 3.2.2.1]