| Message ID | 20240327162918.2426792-2-paweldembicki@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v2,1/3] net: phy: marvell: add basic support of 88E308X/88E609X family | expand |
On Wed, 27 Mar 2024 17:29:13 +0100 Pawel Dembicki wrote: > This commit introduces a new result code: > ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH > which represents the results of a cable test indicating abnormal impedance. I'm not a cable expert but going purely by the language abnormal != mismatch. Mismatch indicates there are two values we are comparing.
pt., 29 mar 2024 o 03:02 Jakub Kicinski <kuba@kernel.org> napisał(a): > > On Wed, 27 Mar 2024 17:29:13 +0100 Pawel Dembicki wrote: > > This commit introduces a new result code: > > ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH > > which represents the results of a cable test indicating abnormal impedance. > > I'm not a cable expert but going purely by the language > abnormal != mismatch. Mismatch indicates there are two > values we are comparing. Impedance mismatch can be detected because some parts of the cable may have different (abnormal) impedance, causing reflections at those points. Ethernet cables should have a characteristic impedance of 100 Ohms, so any mismatch from this value is considered abnormal. I can provide a rephrased version if the commit description was not detailed enough.
On Fri, 29 Mar 2024 10:31:10 +0100 Paweł Dembicki wrote: > > I'm not a cable expert but going purely by the language > > abnormal != mismatch. Mismatch indicates there are two > > values we are comparing. > > Impedance mismatch can be detected because some parts of the cable may > have different (abnormal) impedance, causing reflections at those > points. Ethernet cables should have a characteristic impedance of 100 > Ohms, so any mismatch from this value is considered abnormal. I see, makes sense. > I can provide a rephrased version if the commit description was not > detailed enough. That'd be great. Or maybe even better a short comment above the enum entry?
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h index 3f89074aa06c..ecc020bd47d1 100644 --- a/include/uapi/linux/ethtool_netlink.h +++ b/include/uapi/linux/ethtool_netlink.h @@ -515,6 +515,7 @@ enum { ETHTOOL_A_CABLE_RESULT_CODE_OPEN, ETHTOOL_A_CABLE_RESULT_CODE_SAME_SHORT, ETHTOOL_A_CABLE_RESULT_CODE_CROSS_SHORT, + ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH, }; enum {
Some PHYs can recognize during a cable test if the impedance in the cable is okay. This commit introduces a new result code: ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH which represents the results of a cable test indicating abnormal impedance. Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com> --- v2: - introduce patch include/uapi/linux/ethtool_netlink.h | 1 + 1 file changed, 1 insertion(+)