Created attachment 116363 [details] journalctl -k -t kernel > intel_cpu_fifo_underrun_irq_handler-kernel.txt It happens when switching back from VT to X after a couple of seconds of flickering. It was found while investigating on: https://bugs.freedesktop.org/show_bug.cgi?id=88944 $ cat /proc/cmdline BOOT_IMAGE=/vmlinuz-4.0.4-303.fc22.x86_64 root=UUID=6d95a3dd-0830-4bf9-94c1-a37232327df9 ro rootflags=subvol=root rd.luks.uuid=luks-81064417-7468-43b9-8e39-2e5e9e332d40 rd.luks.uuid=luks-87e2654d-afaa-402c-a4a7-1d6aa1e2403b rhgb quiet systemd.log_level=debug systemd.log_target=kmsg log_buf_len=1M drm.debug=0xe $ uname -a Linux winston 4.0.4-303.fc22.x86_64 #1 SMP Thu May 28 12:37:06 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux $ cat /etc/system-release Fedora release 22 (Twenty Two)
This might be a duplicate of bug 85583. Could you boot with i915.enable_ips=0 in your kernel command line and report back?
i915.enable_ips=0 fixes this problem for me. No flickering, no FIFO underrun.
*** This bug has been marked as a duplicate of bug 85583 ***
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