[BXT] "*ERROR* mismatch in DDB state pipe A plane 1"
Between following drm-tip kernel versions:
- 2020-11-12 14:05:37 5611d7debe: drm-tip: 2020y-11m-12d-14h-02m-08s UTC integration manifest
- 2020-11-17 17:36:53 8dc6152ada: drm-tip: 2020y-11m-17d-17h-35m-37s UTC integration manifest
This ERROR started to appear in dmesg on every boot of one J4205 device:
$ dmesg | fgrep -e '[drm]' -e '[i915]'
[ 3.413513] i915 0000:00:02.0: [drm] GuC firmware i915/bxt_guc_49.0.1.bin: fetch failed with error -2
[ 3.413515] i915 0000:00:02.0: [drm] GuC firmware(s) can be downloaded from https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/i915
[ 3.414358] i915 0000:00:02.0: [drm] GuC is uninitialized
[ 3.415348] i915 0000:00:02.0: [drm] Finished loading DMC firmware i915/bxt_dmc_ver1_07.bin (v1.7)
[ 3.440298] i915 0000:00:02.0: [drm] *ERROR* mismatch in DDB state pipe A plane 1 (expected (0,0), found (0,254))
[ 3.471013] [drm] Initialized i915 1.6.0 20201103 for 0000:00:02.0 on minor 0
[ 3.476589] snd_hda_intel 0000:00:0e.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[ 3.580366] i915 0000:00:02.0: [drm] fb0: i915drmfb frame buffer device
But it doesn't appear in dmesg of another J4205 device (which output is same except for missing the ERROR output). Both have the same stepping, microcode version, Asrock J4205-ITX motherboard, AMI BIOS version (P1.40), kernel and kernel command line options.
Only difference is that one of them starts Ubuntu and another ClearLinux distro, which affects a bit what user-space stuff could ran before 3.4s into the boot process (e.g. Ubuntu uses powersave/ondemand governor, whereas ClearLinux uses performance one). Device with Ubuntu is the one showing the ERROR.
PS. Similar ERROR had been filed for SKL as #2708 (closed), but closed as not any more appearing in CI logs. It happens every night on Ubuntu BXT J4205 though.