https://feedback.corp.google.com/#/Report/15454221020

https://feedback.corp.google.com/#/Report/17240145440

I have no idea about this. Have you only seen it once?

The problem isn't reflected in the screenshot uploaded with the feedback report. I assume that the backlight somehow got into a bad state and turning it off and back on unwedged it.

I've seen it 3 times on the same device.  You're right the screenshot doesn't show it since it's backlight related.

I have seen similar but not the same issue(like a year ago), and I can not find the bug I updated. I see a single feedback that describes it, but not the same case - https://feedback.corp.google.com/product/208/neutron?lView=rd&lRSort=1&lReport=10096028470


For the second feedback reports patricia@ posted I see a 'WARNING: CPU' in Dmesg, before the suspend is finished:
[12364.533936] ------------[ cut here ]------------
[12364.533948] WARNING: CPU: 0 PID: 2681 at /mnt/host/source/src/third_party/kernel/v3.14/drivers/gpu/drm/i915/intel_display.c:767 intel_wait_for_vblank+0xe0/0x1ce()
[12364.533958] vblank wait timed out
[12364.533961] Modules linked in: ip6t_REJECT ip6table_raw ip6table_mangle xt_TCPMSS veth ctr ccm evdi uinput i2c_dev x86_pkg_temp_thermal ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat iwlmvm rfcomm memc_x86 xt_mark aesni_intel aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd snd_hda_codec_hdmi iwlwifi snd_soc_sst_bdw_rt5677_mach iwl7000_mac80211 zram snd_hda_intel bridge snd_hda_controller snd_hda_codec stp llc snd_hwdep acpi_als industrialio_triggered_buffer fuse snd_soc_sst_haswell_pcm snd_soc_rt5677 snd_soc_sst_dsp snd_soc_sst_acpi snd_soc_rl6231 snd_soc_rt5677_spi cfg80211 nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables btusb btbcm btintel bluetooth iio_trig_sysfs joydev cros_ec_accel kfifo_buf industrialio uvcvideo videobuf2_vmalloc snd_seq_midi snd_seq_midi_event snd_rawmidi
[12364.534076]  snd_seq snd_seq_device ppp_async ppp_generic slhc tun
[12364.534088] CPU: 0 PID: 2681 Comm: DrmThread Tainted: G        W    3.14.0 #1
[12364.534094] Hardware name: GOOGLE Samus, BIOS Google_Samus.6300.174.0 04/02/2015
[12364.534100]  0000000000000000 0000000073a43e65 ffff88045e34b9e0 ffffffffa2be1c38
[12364.534109]  ffff88045e34ba28 ffff88045e34ba18 ffffffffa263e217 ffffffffa292decf
[12364.534118]  ffff88046bbc0000 0000000000070040 0000000000008a38 0000000100b7f006
[12364.534127] Call Trace:
[12364.534135]  [<ffffffffa2be1c38>] dump_stack+0x4d/0x6f
[12364.534143]  [<ffffffffa263e217>] warn_slowpath_common+0x7f/0x98
[12364.534150]  [<ffffffffa292decf>] ? intel_wait_for_vblank+0xe0/0x1ce
[12364.534157]  [<ffffffffa263e287>] warn_slowpath_fmt+0x57/0x73
[12364.534165]  [<ffffffffa29657a1>] ? gen6_read32+0xa4/0xb2
[12364.534171]  [<ffffffffa292decf>] intel_wait_for_vblank+0xe0/0x1ce
[12364.534177]  [<ffffffffa293260f>] hsw_disable_ips+0x12b/0x14d
[12364.534183]  [<ffffffffa2933fbd>] haswell_crtc_disable+0x6e/0x293
[12364.534189]  [<ffffffffa2934dc1>] __intel_set_mode+0x78a/0x11ba
[12364.534196]  [<ffffffffa2be94db>] ? _raw_spin_unlock+0xe/0x21
[12364.534202]  [<ffffffffa2be7ae6>] ? __ww_mutex_lock_slowpath+0x286/0x2d9
[12364.534210]  [<ffffffffa293792f>] intel_set_mode+0x14/0x2a
[12364.534215]  [<ffffffffa29382e5>] intel_crtc_set_config+0x89c/0x95a
[12364.534223]  [<ffffffffa28f8ff7>] ? drm_crtc_check_state+0x6c/0x221
[12364.534230]  [<ffffffffa28f667f>] drm_mode_set_config_internal+0x5b/0xe5
[12364.534237]  [<ffffffffa290355d>] commit_crtc_state+0x165/0x21c
[12364.534244]  [<ffffffffa2903108>] atomic_commit.isra.3+0x54/0xae
[12364.534250]  [<ffffffffa2903173>] drm_atomic_commit+0x11/0x13
[12364.534256]  [<ffffffffa28f9fba>] drm_mode_setcrtc+0x2f2/0x392
[12364.534264]  [<ffffffffa28eb9d8>] drm_ioctl+0x2f2/0x421
[12364.534270]  [<ffffffffa28f9cc8>] ? drm_mode_setplane+0x9c/0x9c
[12364.534278]  [<ffffffffa27f1beb>] ? ioctl_has_perm+0xa8/0xed
[12364.534285]  [<ffffffffa272ff09>] do_vfs_ioctl+0x355/0x416
[12364.534291]  [<ffffffffa2730021>] SyS_ioctl+0x57/0x79
[12364.534298]  [<ffffffffa2bea75f>] tracesys+0xe7/0xec
[12364.534303] ---[ end trace 5ff6ef8f9e130cdd ]---

Not sure if related though.

Ken, any thoughts on LED strings layout etc. that could cause this?  On Pixel-C we ran into a bunch of half screen issues (for understandable reasons since Pixel-C display had two separate controllers) but on Samus this seems surprising.

Sameer, Any chance I can get a picture? Without seeing a picture, Samus has 12 LED strings coming back to MLB and one of the strings could have a bad contact at MLB. In future, we plan to use LED driver with fewer strings to reduce failure due to connection.

Picture of the dim screen.  Right hand side is dim.

Deleted: Dimscreen.jpg 4.0 MB

	Dimscreen.jpg 4.0 MB View Download

The attachment doesn't seem downloadable -- I get "Failed - No file" in the download bar. Mind uploading again?

reattached

Happened again this morning when resuming.

Deleted: DimScreen9916.jpg 2.7 MB

	DimScreen9916.jpg 2.7 MB View Download

Ken, thoughts on what could cause this to happen?  I have a hard time coming up with a theory where software could be messing this up by itself.

Same issue observed on samus PVT board at beta channel build 8530.90.0 / 53.0.2785.129
Happened after device experienced some zoom-in and -out UI issues and thus reboot.

I believe this is the same PVT batch from which patricia@ has her board too.

Feedback: https://feedback.corp.google.com/product/208/neutron?lView=rd&lReport=13820971217

Generated logs and screenshot at https://pantheon.corp.google.com/storage/browser/chromiumos-test-logs/bugfiles/cr/639306/?pli=1

We have had a couple users report the same problem on CBC
https://productforums.google.com/forum/#!topic/chromebook-central/daNZFL9VG6I;context-place=topicsearchin/chromebook-central/pixel$20screen$20half

#CBC-RS/TC-watchlist

Ken, any idea how this could occur? Probably not feasible or necessary to fix on Samus at this point, but may hold a good lesson

The assigned owner "kenfoo@chromium.org" is not able to receive e-mails, please re-triage.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

ok that solves the problem then