# Linux PTP versions on the Ouster Sensor **URL:** \ **Category:** Software\ **Tags:** ptp, time-synchronization, firmware\ **Created:** [May 16, 2024, 5:21pm UTC](https://community.ouster.com/t/linux-ptp-versions-on-the-ouster-sensor/102 "2024-05-16T17:21:44Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![kbear](https://yyz2.discourse-cdn.com/flex004/user_avatar/community.ouster.com/kbear/32/62_2.png) [@kbear](https://community.ouster.com/u/kbear)\ **Post date:** [May 16, 2024, 5:21pm UTC](https://community.ouster.com/t/linux-ptp-versions-on-the-ouster-sensor/102/1 "2024-05-16T17:21:44Z")
The Ouster sensors achieve PTP time synchronization through the use of verbatim Linux PTP (aka ptp4l). # LinuxPTP versions Here are the linuxptp versions listed by Ouster firmware version: - Ouster FW v3.0.1: - `linuxptp cortexa53 3.1.1` - Ouster FW v3.1.0: - `linuxptp cortexa53 4.1` # Patch for protocol version Additionally, there is a recommended patch for customers to force their client PTP\_VERSION (protocol version not linuxptp version) to 2.0 instead of 2.1. Ouster sensors advertise v2.0 linuxptp _protocol_ to avoid customer compatibility problems with post v4.0 linuxptp versions Here is a [link](https://sourceforge.net/p/linuxptp/mailman/linuxptp-devel/thread/20210221153233.GA26452%40hoboy.vegasvil.org/#msg37224462) to the source/fix of the problem in the PTP mailing list. Date: Mon, 2 Oct 2023 11:28:37 -0700 Subject: [PATCH] msg: rollback PTP\_VERSION to 2.0 to workaround hw issues - Many devices have issues with timestamping inbound/outbound packets with the version set v2.1 which results in breakage. - Rolling this back seems to have almost no impact other than we advertise a lower version. - Introduced by commit: 2a2532d66121d0060b042c5bd6020a62153f1e0a ```auto --- msg.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/msg.h b/msg.h index 484435d..ffc49d4 100644 --- a/msg.h +++ b/msg.h @@ -32,7 +32,7 @@ # Version definition for IEEE 1588-2019 #define PTP_MAJOR_VERSION 2 -#define PTP_MINOR_VERSION 1 +#define PTP_MINOR_VERSION 0 /* BUG: rollback for customer hw compatibility */ #define PTP_VERSION (PTP_MINOR_VERSION << 4 | PTP_MAJOR_VERSION) #define MAJOR_VERSION_MASK 0x0f` -- 2.34.1 ```