[Regression] Colour banding appears on Lenovo B50-80 integrated display

Bug #1788308 reported by Wojciech on 2018-08-21
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Medium
Kai-Heng Feng

Bug Description

The problem affects the integrated display on a Lenovo B50-80 notebook.

Colour banding is visible everywhere on the system, as dithering seems not to be enabled on this 6bpp display. This issue was not present on non-HWE Ubuntu 16.04, and it showed up after I upgraded to Ubuntu 18.04. There was already a very similar bug #1749420 that had a fix released, however, because the make and model of an LCD screen in that case was different, the quirk added to the kernel did not address the problem that affects my machine. The cause of this issue is probably the same, since I have checked that pre-4.8.0-rc2 kernels handled dithering correctly, and 4.8.0-rc2 and later kernels already had the bug described. I believe that adding quirk for an another type of display may fix the problem.

I attached the results of running
sudo get-edid | parse-edid in a file named edid.txt
and
sudo get-edid | edid-decode in a file named edid-decoded.txt.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-32-generic 4.15.0-32.35
ProcVersionSignature: Ubuntu 4.15.0-32.35-generic 4.15.18
Uname: Linux 4.15.0-32-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: me 1245 F.... pulseaudio
 /dev/snd/controlC1: me 1245 F.... pulseaudio
Date: Wed Aug 22 00:26:15 2018
HibernationDevice: RESUME=UUID=93b28df5-b453-452b-960d-7173994d778e
InstallationDate: Installed on 2018-08-21 (0 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
MachineType: LENOVO 80EW
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-32-generic root=UUID=a1cd5b8c-2707-4840-858b-3ca12517193b ro quiet splash vt.handoff=1
PulseList:
 Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied
 No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-32-generic N/A
 linux-backports-modules-4.15.0-32-generic N/A
 linux-firmware 1.173.1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/02/2016
dmi.bios.vendor: LENOVO
dmi.bios.version: A8CN54WW(V3.07)
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: Lenovo B50-80
dmi.board.vendor: LENOVO
dmi.board.version: 31900058 WIN
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo B50-80
dmi.modalias: dmi:bvnLENOVO:bvrA8CN54WW(V3.07):bd09/02/2016:svnLENOVO:pn80EW:pvrLenovoB50-80:rvnLENOVO:rnLenovoB50-80:rvr31900058WIN:cvnLENOVO:ct10:cvrLenovoB50-80:
dmi.product.family: IDEAPAD
dmi.product.name: 80EW
dmi.product.version: Lenovo B50-80
dmi.sys.vendor: LENOVO

CVE References

Wojciech (wk304) wrote :
Wojciech (wk304) wrote :
Wojciech (wk304) wrote :
Wojciech (wk304) wrote :
Wojciech (wk304) wrote :

This change was made by a bot.

Changed in linux (Ubuntu):
status: New → Confirmed
Wojciech (wk304) on 2018-08-22
description: updated
Joseph Salisbury (jsalisbury) wrote :

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.18 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.18.3

Changed in linux (Ubuntu):
importance: Undecided → Medium
status: Confirmed → Incomplete
tags: added: kernel-da-key
Wojciech (wk304) wrote :

Hello Joseph,

Thank you for your response. Unfortunately, installing and running the latest upstream kernel, version 4.18.4-041804.201808220230, did not solve my problem - the banding is still clearly visible, so I added an appropriate tag.

tags: added: kernel-bug-exists-upstream
Changed in linux (Ubuntu):
status: Incomplete → Confirmed
Kai-Heng Feng (kaihengfeng) wrote :
Wojciech (wk304) wrote :

It worked like a charm - there is no more banding issue. Thank you very much, Kai-Heng! Should this fix be checked on other versions of Ubuntu, just let me know.

Kai-Heng Feng (kaihengfeng) wrote :
Changed in linux (Ubuntu):
assignee: nobody → Kai-Heng Feng (kaihengfeng)
Kai-Heng Feng (kaihengfeng) wrote :

This should be fixed by next stable kernel update.

Seth Forshee (sforshee) on 2018-10-05
Changed in linux (Ubuntu):
status: Confirmed → Fix Committed
Launchpad Janitor (janitor) wrote :
Download full text (60.2 KiB)

This bug was fixed in the package linux - 4.18.0-9.10

---------------
linux (4.18.0-9.10) cosmic; urgency=medium

  * linux: 4.18.0-9.10 -proposed tracker (LP: #1796346)

  * Cosmic update: v4.18.12 upstream stable release (LP: #1796139)
    - crypto: skcipher - Fix -Wstringop-truncation warnings
    - iio: adc: ina2xx: avoid kthread_stop() with stale task_struct
    - tsl2550: fix lux1_input error in low light
    - misc: ibmvmc: Use GFP_ATOMIC under spin lock
    - vmci: type promotion bug in qp_host_get_user_memory()
    - siox: don't create a thread without starting it
    - x86/numa_emulation: Fix emulated-to-physical node mapping
    - staging: rts5208: fix missing error check on call to rtsx_write_register
    - power: supply: axp288_charger: Fix initial constant_charge_current value
    - misc: sram: enable clock before registering regions
    - serial: sh-sci: Stop RX FIFO timer during port shutdown
    - uwb: hwa-rc: fix memory leak at probe
    - power: vexpress: fix corruption in notifier registration
    - iommu/amd: make sure TLB to be flushed before IOVA freed
    - Bluetooth: Add a new Realtek 8723DE ID 0bda:b009
    - USB: serial: kobil_sct: fix modem-status error handling
    - 6lowpan: iphc: reset mac_header after decompress to fix panic
    - iommu/msm: Don't call iommu_device_{,un}link from atomic context
    - s390/mm: correct allocate_pgste proc_handler callback
    - power: remove possible deadlock when unregistering power_supply
    - drm/amd/display/dc/dce: Fix multiple potential integer overflows
    - drm/amd/display: fix use of uninitialized memory
    - md-cluster: clear another node's suspend_area after the copy is finished
    - cxgb4: Fix the condition to check if the card is T5
    - RDMA/bnxt_re: Fix a couple off by one bugs
    - RDMA/i40w: Hold read semaphore while looking after VMA
    - RDMA/bnxt_re: Fix a bunch of off by one bugs in qplib_fp.c
    - IB/core: type promotion bug in rdma_rw_init_one_mr()
    - media: exynos4-is: Prevent NULL pointer dereference in __isp_video_try_fmt()
    - IB/mlx4: Test port number before querying type.
    - powerpc/kdump: Handle crashkernel memory reservation failure
    - media: fsl-viu: fix error handling in viu_of_probe()
    - vhost_net: Avoid tx vring kicks during busyloop
    - media: staging/imx: fill vb2_v4l2_buffer field entry
    - IB/mlx5: Fix GRE flow specification
    - include/rdma/opa_addr.h: Fix an endianness issue
    - x86/tsc: Add missing header to tsc_msr.c
    - ARM: hwmod: RTC: Don't assume lock/unlock will be called with irq enabled
    - x86/entry/64: Add two more instruction suffixes
    - ARM: dts: ls1021a: Add missing cooling device properties for CPUs
    - scsi: target/iscsi: Make iscsit_ta_authentication() respect the output
      buffer size
    - thermal: i.MX: Allow thermal probe to fail gracefully in case of bad
      calibration.
    - scsi: klist: Make it safe to use klists in atomic context
    - scsi: ibmvscsi: Improve strings handling
    - scsi: target: Avoid that EXTENDED COPY commands trigger lock inversion
    - usb: wusbcore: security: cast sizeof to int for comparison
    - ath10k: sdio: use same endpoint id for all packets...

Changed in linux (Ubuntu):
status: Fix Committed → Fix Released
Wojciech (wk304) on 2018-10-13
tags: added: verification-done-cosmic
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