A possible cause for this bug has occurred to me, but I wouldn't know where in the kernel code to check for this.
Note: When I talk about a control line, I am using the DTE, i.e computer, end connector reference. In years past there was no standardization for which line on a serial port carried the PPS signal for a GPS and it was a mix of DCD, RTS, and occasionally CTS. Current commercial devices, such as the one I have, seem to mostly use CTS. Is is possible the current kernel code is not looking at ALL those lines for PPS? This would also explain why you have not gotten lots of bug reports as very few people would be running such a device. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1938626 Title: PPS API broken Status in linux package in Ubuntu: New Status in linux source package in Focal: New Bug description: The kernel PPS API appears to be broken. I have a serial GPS with PPS attached to /dev/ttyS4. If I use gpsd to create /dev/pps0, gpsd fails to see PPS data. If I disable gpsd and create /dev/pps0 with ldattach, any app or tool run against ttyS4 works fine and does see the CTS transitions every second, i.e. gpsmon and ppscheck. Anything run against pps0 fails, i.e. ppstest, ppswatch. ntpd gets data from ttyS4 but not pps0. There are some issues with stock apparmor with gpsd and ntpd, but I have solved those. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-80-generic 5.4.0-80.90 ProcVersionSignature: Ubuntu 5.4.0-80.90-generic 5.4.124 Uname: Linux 5.4.0-80-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.18 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: jimp 6811 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: GNOME-Flashback:GNOME Date: Sat Jul 31 16:41:32 2021 HibernationDevice: RESUME=UUID=90289c8f-5a00-46c4-8f1f-79dd26128f39 InstallationDate: Installed on 2016-08-05 (1820 days ago) InstallationMedia: Ubuntu-Server 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-80-generic root=UUID=389dcb0d-84f2-4340-ad6c-e4f1dbe55b67 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-5.4.0-80-generic N/A linux-backports-modules-5.4.0-80-generic N/A linux-firmware 1.187.15 SourcePackage: linux UpgradeStatus: Upgraded to focal on 2020-11-09 (264 days ago) dmi.bios.date: 11/26/2009 dmi.bios.vendor: Intel Corp. dmi.bios.version: TYG4110H.86A.0036.2009.1126.2047 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: DG41TY dmi.board.vendor: Intel Corporation dmi.board.version: AAE47335-302 dmi.chassis.type: 3 dmi.modalias: dmi:bvnIntelCorp.:bvrTYG4110H.86A.0036.2009.1126.2047:bd11/26/2009:svn:pn:pvr:rvnIntelCorporation:rnDG41TY:rvrAAE47335-302:cvn:ct3:cvr: To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1938626/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
