drm: WARNING: __drm_atomic_helper_set_config

From: Jeremiah Mahler
Date: Wed Jan 13 2016 - 00:14:06 EST

all,

Since linux-next 20160111 I have been getting these warnings
sporadically about drm_atomic on my Acer C720 Chromebook during
bootup.

...
[ 2.717031] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
[ 2.717308] ieee80211 phy0: Atheros AR9462 Rev:2 mem=0xffffc90000500000, irq=16
[ 2.785850] snd_hda_intel 0000:00:03.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[ 2.785860] [drm] Initialized i915 1.6.0 20151218 for 0000:00:02.0 on minor 0
[ 2.799423] clocksource: Switched to clocksource tsc
[ 2.920747] ------------[ cut here ]------------
[ 2.920760] WARNING: CPU: 0 PID: 478 at drivers/gpu/drm/drm_atomic_helper.c:1858 __drm_atomic_helper_set_config+0x1e9/0x390 [drm_kms_helper]()
[ 2.920762] Modules linked in: arc4 ath9k i915 ath9k_common ath9k_hw ath mac80211 i2c_algo_bit drm_kms_helper cfg80211 snd_hda_codec_realtek isl29018(C) snd_hda_codec_generic syscopyarea industrialio sysfillrect sysimgblt cyapatp fb_sys_fops snd_hda_intel drm regmap_i2c snd_hda_codec crc_itu_t intel_rapl x86_pkg_temp_thermal intel_powerclamp snd_hwdep coretemp snd_hda_core crct10dif_pclmul crc32_pclmul crc32c_intel snd_pcm ghash_clmulni_intel rfkill chromeos_laptop cryptd snd_timer snd serio_raw pcspkr i2c_i801 sg shpchp soundcore lpc_ich mfd_core i2c_designware_pci i2c_designware_core battery ac video tpm_tis tpm button evdev uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core videodev media i2c_core autofs4 ext4 crc16 mbcache jbd2 sd_mod ahci libahci libata scsi_mod xhci_pci
[ 2.920816] xhci_hcd fan usbcore usb_common thermal sdhci_acpi sdhci mmc_core
[ 2.920825] CPU: 0 PID: 478 Comm: Xorg Tainted: G C 4.4.0-next-20160112+ #100
[ 2.920827] Hardware name: GOOGLE Peppy/Peppy, BIOS 4.0-6588-g4acd8ea-dirty 09/04/2014
[ 2.920829] ffffffffa04d8070 ffffffff81273087 0000000000000000 ffffffff8105bf1d
[ 2.920833] ffff880071417f40 ffff88003647e200 ffff88007484e700 ffff88003578dc00
[ 2.920836] ffff8800747a5000 ffffffffa04d0f39 00000000000001ff ffff880035f20040
[ 2.920839] Call Trace:
[ 2.920847] [<ffffffff81273087>] ? dump_stack+0x40/0x59
[ 2.920852] [<ffffffff8105bf1d>] ? warn_slowpath_common+0x7d/0xb0
[ 2.920857] [<ffffffffa04d0f39>] ? __drm_atomic_helper_set_config+0x1e9/0x390 [drm_kms_helper]
[ 2.920862] [<ffffffffa04d1cc5>] ? restore_fbdev_mode+0x215/0x250 [drm_kms_helper]
[ 2.920866] [<ffffffffa04d3d9e>] ? drm_fb_helper_restore_fbdev_mode_unlocked+0x2e/0x70 [drm_kms_helper]
[ 2.920948] [<ffffffffa064a0be>] ? intel_fbdev_restore_mode+0x1e/0x80 [i915]
[ 2.920994] [<ffffffffa067413a>] ? i915_driver_lastclose+0xa/0x10 [i915]
[ 2.921005] [<ffffffffa0396969>] ? drm_lastclose+0x29/0x130 [drm]
[ 2.921012] [<ffffffffa0396d8a>] ? drm_release+0x31a/0x500 [drm]
[ 2.921018] [<ffffffff811a2ecd>] ? __fput+0xcd/0x1d0
[ 2.921023] [<ffffffff810767e1>] ? task_work_run+0x71/0x90
[ 2.921027] [<ffffffff810012ef>] ? exit_to_usermode_loop+0x9f/0xb0
[ 2.921033] [<ffffffff8146752b>] ? int_ret_from_sys_call+0x25/0x8f
[ 2.921035] ---[ end trace f4ea25d33621d8e3 ]---
[ 2.921051] ------------[ cut here ]------------
[ 2.921060] WARNING: CPU: 0 PID: 478 at drivers/gpu/drm/drm_atomic.c:734 drm_atomic_check_only+0x3b4/0x620 [drm]()
[ 2.921061] Modules linked in: arc4 ath9k i915 ath9k_common ath9k_hw ath mac80211 i2c_algo_bit drm_kms_helper cfg80211 snd_hda_codec_realtek isl29018(C) snd_hda_codec_generic syscopyarea industrialio sysfillrect sysimgblt cyapatp fb_sys_fops snd_hda_intel drm regmap_i2c snd_hda_codec crc_itu_t intel_rapl x86_pkg_temp_thermal intel_powerclamp snd_hwdep coretemp snd_hda_core crct10dif_pclmul crc32_pclmul crc32c_intel snd_pcm ghash_clmulni_intel rfkill chromeos_laptop cryptd snd_timer snd serio_raw pcspkr i2c_i801 sg shpchp soundcore lpc_ich mfd_core i2c_designware_pci i2c_designware_core battery ac video tpm_tis tpm button evdev uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core videodev media i2c_core autofs4 ext4 crc16 mbcache jbd2 sd_mod ahci libahci libata scsi_mod xhci_pci
[ 2.921110] xhci_hcd fan usbcore usb_common thermal sdhci_acpi sdhci mmc_core
[ 2.921117] CPU: 0 PID: 478 Comm: Xorg Tainted: G WC 4.4.0-next-20160112+ #100
[ 2.921119] Hardware name: GOOGLE Peppy/Peppy, BIOS 4.0-6588-g4acd8ea-dirty 09/04/2014
[ 2.921121] ffffffffa03c7707 ffffffff81273087 0000000000000000 ffffffff8105bf1d
[ 2.921125] 0000000000000000 ffff88007484e700 ffff88003647e200 ffff8800749cc000
[ 2.921129] 0000000000000001 ffffffffa03b2054 ffff880071417fc0 ffff88006a90c000
[ 2.921132] Call Trace:
[ 2.921139] [<ffffffff81273087>] ? dump_stack+0x40/0x59
[ 2.921144] [<ffffffff8105bf1d>] ? warn_slowpath_common+0x7d/0xb0
[ 2.921151] [<ffffffffa03b2054>] ? drm_atomic_check_only+0x3b4/0x620 [drm]
[ 2.921157] [<ffffffffa03b2802>] ? drm_atomic_add_affected_connectors+0x22/0xf0 [drm]
[ 2.921164] [<ffffffffa03b22d2>] ? drm_atomic_commit+0x12/0x60 [drm]
[ 2.921169] [<ffffffffa04d1cd3>] ? restore_fbdev_mode+0x223/0x250 [drm_kms_helper]
[ 2.921173] [<ffffffffa04d3d9e>] ? drm_fb_helper_restore_fbdev_mode_unlocked+0x2e/0x70 [drm_kms_helper]
[ 2.921217] [<ffffffffa064a0be>] ? intel_fbdev_restore_mode+0x1e/0x80 [i915]
[ 2.921261] [<ffffffffa067413a>] ? i915_driver_lastclose+0xa/0x10 [i915]
[ 2.921268] [<ffffffffa0396969>] ? drm_lastclose+0x29/0x130 [drm]
[ 2.921274] [<ffffffffa0396d8a>] ? drm_release+0x31a/0x500 [drm]
[ 2.921279] [<ffffffff811a2ecd>] ? __fput+0xcd/0x1d0
[ 2.921283] [<ffffffff810767e1>] ? task_work_run+0x71/0x90
[ 2.921286] [<ffffffff810012ef>] ? exit_to_usermode_loop+0x9f/0xb0
[ 2.921291] [<ffffffff8146752b>] ? int_ret_from_sys_call+0x25/0x8f
[ 2.921293] ---[ end trace f4ea25d33621d8e4 ]---
[ 2.922971] fbcon: inteldrmfb (fb0) is primary device
[ 4.137640] Console: switching to colour frame buffer device 170x48
[ 4.271184] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 4.318794] input: HDA Intel HDMI HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:03.0/sound/card0/input13
[ 4.318900] input: HDA Intel HDMI HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:03.0/sound/card0/input14
[ 4.318993] input: HDA Intel HDMI HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:03.0/sound/card0/input15
...

I haven't figured out what is wrong yet and performing a bisect is
not practical since it is sporadic. Any suggestions or ideas are
welcome.

--
- Jeremiah Mahler