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authorAntoine Tenart <antoine.tenart@bootlin.com>2018-05-04 18:21:03 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-03 08:47:53 +0300
commitaf4a392e5a15920e7a337fae01a5f866cb9f605c (patch)
treea23a71688431f0b75a381e3d745be7d23fd978d8
parent8410a8ddfea1c80b9d9532bdbc5972850c6b2b08 (diff)
downloadlinux-af4a392e5a15920e7a337fae01a5f866cb9f605c.tar.xz
net: phy: sfp: handle cases where neither BR, min nor BR, max is given
[ Upstream commit 2b999ba899059eed00a03d029894a62486e7e2bc ] When computing the bitrate using values read from an SFP module EEPROM, we use the nominal BR plus BR,min and BR,max to determine the boundaries. But in some cases BR,min and BR,max aren't provided, which led the SFP code to end up having the nominal value for both the minimum and maximum bitrate values. When using a passive cable, the nominal value should be used as the maximum one, and there is no minimum one so we should use 0. Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com> Acked-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/phy/sfp-bus.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
index fd6c23f69c2f..d437f4f5ed52 100644
--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -132,6 +132,13 @@ void sfp_parse_support(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
br_max = br_nom + br_nom * id->ext.br_min / 100;
br_min = br_nom - br_nom * id->ext.br_min / 100;
}
+
+ /* When using passive cables, in case neither BR,min nor BR,max
+ * are specified, set br_min to 0 as the nominal value is then
+ * used as the maximum.
+ */
+ if (br_min == br_max && id->base.sfp_ct_passive)
+ br_min = 0;
}
/* Set ethtool support from the compliance fields. */