Messages in this thread | | | Date | Wed, 17 Apr 2024 20:39:54 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH net-next v1 2/4] net: phy: micrel: lan8841: set default PTP latency values |
| |
On Wed, Apr 17, 2024 at 06:43:14PM +0200, Oleksij Rempel wrote: > Set default PTP latency values to provide realistic path delay > measurements and reflecting internal PHY latency asymetry. > > This values are based on ptp4l measurements for the path delay against > identical PHY as link partner and latency asymmetry extracted from > documented SOF Latency values of this PHY. > > Documented SOF Latency values are: > TX 138ns/RX 430ns @ 1000Mbps > TX 140ns/RX 615ns @ 100Mbps (fixed latency mode) > TX 140ns/RX 488-524ns @ 100Mbps (variable latency mode) > TX 654ns/227-2577ns @ 10Mbps
Does Half Duplex vs Full Duplex make a difference here?
> +static int lan8841_ptp_latency_init(struct phy_device *phydev) > +{ > + int ret; > + > + ret = phy_write_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, > + LAN8841_PTP_RX_LATENCY_10M, > + LAN8841_PTP_RX_LATENCY_10M_VAL); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, > + LAN8841_PTP_TX_LATENCY_10M, > + LAN8841_PTP_TX_LATENCY_10M_VAL); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, > + LAN8841_PTP_RX_LATENCY_100M, > + LAN8841_PTP_RX_LATENCY_100M_VAL); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, > + LAN8841_PTP_TX_LATENCY_100M, > + LAN8841_PTP_TX_LATENCY_100M_VAL); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, > + LAN8841_PTP_RX_LATENCY_1000M, > + LAN8841_PTP_RX_LATENCY_1000M_VAL); > + if (ret) > + return ret; > + > + return phy_write_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, > + LAN8841_PTP_TX_LATENCY_1000M, > + LAN8841_PTP_TX_LATENCY_1000M_VAL); > +}
What affect does this have on systems which have already applied adjustments in user space to correct for this? Will this cause regressions for such systems?
I know Richard has rejected changes like this in the past.
Andrew
| |