Public bug reported:
Dear Launchpad readers,
Changes to a 40Hz-based mode are adjusted back to a 60Hz display mode by
KMS, as can be seen in the logs with the drm.debug=4 option :
oct. 18 16:27:24 NovHak-P2 kernel: [drm:intel_dump_pipe_config [i915]]
requested mode:
oct. 18 16:27:24 NovHak-P2 kernel: [drm:drm_mode_debug_printmodeline [drm]]
Modeline 0:"" 0 92450 1920 1968 2000 2080 1080 1083 1088 1111 0x0 0x9
oct. 18 16:27:24 NovHak-P2 kernel: [drm:intel_dump_pipe_config [i915]] adjusted
mode:
oct. 18 16:27:24 NovHak-P2 kernel: [drm:drm_mode_debug_printmodeline [drm]]
Modeline 0:"1920x1080" 60 140490 1920 1972 2007 2094 1080 1083 1089 1118 0x48
0x9
I managed to have 40Hz through EDID modification, swapping the two DTDs
it contains, one being 60Hz, the other 40Hz, hence placing the 40Hz DTD
first, but then it remains sticked to 40Hz and unable to switch to a
60Hz mode.
I suppose the bug is i915-related rather than Xorg-related, since the
modelines seem correctly sent for KMS.
I can provide additional information if needed.
ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: linux-image-generic 5.0.0.32.33
ProcVersionSignature: Ubuntu 5.0.0-32.34-generic 5.0.21
Uname: Linux 5.0.0-32-generic x86_64
ApportVersion: 2.20.10-0ubuntu27.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC2: olivier 12097 F.... pulseaudio
/dev/snd/controlC0: olivier 12097 F.... pulseaudio
/dev/snd/controlC1: olivier 12097 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Fri Oct 18 16:43:01 2019
InstallationDate: Installed on 2019-09-22 (26 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
MachineType: Notebook P17SM-A
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=fr_FR.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.0.0-32-generic
root=UUID=788f8a5e-9667-4cfb-abf4-bc76ebcb86bb ro quiet splash
mtrr_spare_reg_nr=0 vt.handoff=1
RelatedPackageVersions:
linux-restricted-modules-5.0.0-32-generic N/A
linux-backports-modules-5.0.0-32-generic N/A
linux-firmware 1.178.3
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/27/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 4.6.5
dmi.board.asset.tag: Tag 12345
dmi.board.name: P17SM-A
dmi.board.vendor: Notebook
dmi.board.version: Not Applicable
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd03/27/2014:svnNotebook:pnP17SM-A:pvrNotApplicable:rvnNotebook:rnP17SM-A:rvrNotApplicable:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: Not Applicable
dmi.product.name: P17SM-A
dmi.product.sku: Not Applicable
dmi.product.version: Not Applicable
dmi.sys.vendor: Notebook
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug disco
** Attachment added: "Modified EDID"
https://bugs.launchpad.net/bugs/1848746/+attachment/5298241/+files/EDID-modded.bin
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https://bugs.launchpad.net/bugs/1848746
Title:
Refresh rate change requests to 40Hz are "adjusted" back to 60Hz
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