igt@kms_color@.* | igt@kms_plane_scaling@.* - dmesg-warn/fail - *ERROR* CPU pipe A FIFO underrun

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_1234/fi-kbl-soraka/igt@kms_plane_scaling@plane-upscale-with-modifiers-20x20@pipe-a-edp-1.html#dmesg-warnings124

7> [747.184338] i915 0000:00:02.0: [drm:drm_mode_addfb2] [FB:141]
<7> [747.207859] i915 0000:00:02.0: [drm:skl_update_scaler [i915]] scaler_user index 0.0: staged scaling request for 20x20->2400x1600 scaler_users = 0x1
<7> [747.209613] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   level *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm -> *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm
<7> [747.210750] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   lines    0,   3,   4,   4,   7,   8,   9,  11,   0,   0,    0 ->    0,   3,   4,   4,   7,   8,   9,  11,   0,   0,    0
<7> [747.212223] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]  blocks   13,  48,  66,  74, 135, 162, 174, 206,   0,   0,    0 ->   13,  13,  13,  13,  16,  18,  20,  24,   0,   0,    0
<7> [747.214230] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A] min_ddb   14,  49,  67,  75, 136, 163, 175, 207,   0,   0,    0 ->   14,  14,  14,  14,  17,  19,  21,  25,   0,   0,    0
<7> [747.215781] i915 0000:00:02.0: [drm:intel_atomic_setup_scalers [i915]] Attached scaler id 0.0 to PLANE:31
<7> [747.247564] i915 0000:00:02.0: [drm:i915_fifo_underrun_reset_write [i915]] Re-arming FIFO underruns on pipe A
<7> [747.251427] i915 0000:00:02.0: [drm:drm_mode_addfb2] [FB:97]
<7> [747.256794] i915 0000:00:02.0: [drm:skl_update_scaler [i915]] scaler_user index 0.0: staged scaling request for 20x20->2400x1600 scaler_users = 0x1
<7> [747.258717] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   level *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm -> *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm
<7> [747.260265] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   lines    0,   3,   4,   4,   7,   8,   9,  11,   0,   0,    0 ->    0,   4,   5,   6,   9,  10,  11,  12,   0,   0,    0
<7> [747.261565] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]  blocks   13,  13,  13,  13,  16,  18,  20,  24,   0,   0,    0 ->    4,   6,   7,   8,  11,  12,  13,  14,   0,   0,    0
<7> [747.263248] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A] min_ddb   14,  14,  14,  14,  17,  19,  21,  25,   0,   0,    0 ->    5,   7,   8,   9,  12,  13,  14,  15,   0,   0,    0
<7> [747.264746] i915 0000:00:02.0: [drm:intel_atomic_setup_scalers [i915]] Attached scaler id 0.0 to PLANE:31
<7> [747.269256] i915 0000:00:02.0: [drm:intel_fbc_update [i915]] reserved 20480 bytes of contiguous stolen space for FBC, limit: 1
<7> [747.270781] i915 0000:00:02.0: [drm:intel_fbc_update [i915]] Enabling FBC on [PLANE:31:plane 1A]
<7> [747.280184] i915 0000:00:02.0: [drm:drm_mode_addfb2] [FB:142]
<3> [747.318028] i915 0000:00:02.0: [drm] *ERROR* CPU pipe A FIFO underrun
<7> [747.320945] i915 0000:00:02.0: [drm:intel_fbc_underrun_work_fn [i915]] Disabling FBC due to FIFO underrun.
<7> [747.328908] i915 0000:00:02.0: [drm:__intel_fbc_disable [i915]] Disabling FBC on [PLANE:31:plane 1A]
<7> [747.358569] i915 0000:00:02.0: [drm:skl_update_scaler [i915]] scaler_user index 0.0: staged scaling request for 20x20->2400x1600 scaler_users = 0x1
<7> [747.360912] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   level *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm -> *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm
<7> [747.362204] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   lines    0,   4,   5,   6,   9,  10,  11,  12,   0,   0,    0 ->    0,  16,  16,  16,  16,  16,  17,  19,   0,   0,    0
<7> [747.363574] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]  blocks    4,   6,   7,   8,  11,  12,  13,  14,   0,   0,    0 ->    3,   5,   5,   5,   5,   5,   6,   6,   0,   0,    0
<7> [747.365091] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A] min_ddb    5,   7,   8,   9,  12,  13,  14,  15,   0,   0,    0 ->    4,   6,   6,   6,   6,   6,   7,   7,   0,   0,    0
<7> [747.366425] i915 0000:00:02.0: [drm:intel_atomic_setup_scalers [i915]] Attached scaler id 0.0 to PLANE:31
<7> [747.379664] i915 0000:00:02.0: [drm:drm_mode_addfb2] [FB:143]
<7> [747.440254] i915 0000:00:02.0: [drm:skl_update_scaler [i915]] scaler_user index 0.0: staged scaling request for 20x20->2400x1600 scaler_users = 0x1
<7> [747.441908] i915 0000:00:02.0: [drm:intel_atomic_setup_scalers [i915]] Attached scaler id 0.0 to PLANE:31
<7> [747.462798] i915 0000:00:02.0: [drm:drm_mode_addfb2] [FB:144]
<7> [747.466861] i915 0000:00:02.0: [drm:skl_update_scaler [i915]] scaler_user index 0.0: Staged freeing scaler id 0 scaler_users = 0x0
<7> [747.468251] i915 0000:00:02.0: [drm:skl_update_scaler [i915]] scaler_user index 0.1: staged scaling request for 20x20->2400x1600 scaler_users = 0x2
<7> [747.469766] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A] ddb (   0 -  856) -> (   0 -    0), size  856 ->    0
<7> [747.471303] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A] ddb (   0 -    0) -> (   0 -  856), size    0 ->  856
<7> [747.472433] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   level *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm ->  wm0, wm1, wm2, wm3, wm4, wm5, wm6, wm7, twm, swm, stwm
<7> [747.473874] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]   lines    0,  16,  16,  16,  16,  16,  17,  19,   0,   0,    0 ->    0,   0,   0,   0,   0,   0,   0,   0,   0,   0,    0
<7> [747.475398] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A]  blocks    3,   5,   5,   5,   5,   5,   6,   6,   0,   0,    0 ->    0,   0,   0,   0,   0,   0,   0,   0,   0,   0,    0
<7> [747.477254] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:31:plane 1A] min_ddb    4,   6,   6,   6,   6,   6,   7,   7,   0,   0,    0 ->    0,   0,   0,   0,   0,   0,   0,   0,   0,   0,    0
<7> [747.478508] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A]   level  wm0, wm1, wm2, wm3, wm4, wm5, wm6, wm7, twm, swm, stwm -> *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm
<7> [747.479958] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A]   lines    0,   0,   0,   0,   0,   0,   0,   0,   0,   0,    0 ->    0,   3,   4,   4,   7,   8,   9,  11,   0,   0,    0
<7> [747.481240] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A]  blocks    0,   0,   0,   0,   0,   0,   0,   0,   0,   0,    0 ->   13,  13,  13,  13,  16,  18,  20,  24,   0,   0,    0
<7> [747.482685] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A] min_ddb    0,   0,   0,   0,   0,   0,   0,   0,   0,   0,    0 ->   14,  14,  14,  14,  17,  19,  21,  25,   0,   0,    0
<7> [747.484253] i915 0000:00:02.0: [drm:intel_atomic_setup_scalers [i915]] Attached scaler id 0.0 to PLANE:39
<7> [747.496127] i915 0000:00:02.0: [drm:drm_mode_addfb2] [FB:145]
<7> [747.500234] i915 0000:00:02.0: [drm:skl_update_scaler [i915]] scaler_user index 0.1: staged scaling request for 20x20->2400x1600 scaler_users = 0x2
<7> [747.501789] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A]   level *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm -> *wm0,*wm1,*wm2,*wm3,*wm4,*wm5,*wm6,*wm7, twm, swm, stwm
<7> [747.503108] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A]   lines    0,   3,   4,   4,   7,   8,   9,  11,   0,   0,    0 ->    0,   4,   5,   6,   9,  10,  11,  12,   0,   0,    0
<7> [747.504830] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A]  blocks   13,  13,  13,  13,  16,  18,  20,  24,   0,   0,    0 ->    4,   6,   7,   8,  11,  12,  13,  14,   0,   0,    0
<7> [747.506218] i915 0000:00:02.0: [drm:skl_compute_wm [i915]] [PLANE:39:plane 2A] min_ddb   14,  14,  14,  14,