You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
36 lines
1.3 KiB
Diff
36 lines
1.3 KiB
Diff
From: Russell King <rmk+kernel@armlinux.org.uk>
|
|
Date: Thu, 5 Jan 2017 00:23:40 +0000
|
|
Subject: [PATCH] net: phy: don't double-read clause 45 status register
|
|
|
|
One of the design decisions behind the link status bit in the status
|
|
register is that it latches low on link loss. This is so that link loss
|
|
events are not missed. Double-reading the status register means that we
|
|
always read the current state of the link, clearing any link loss event.
|
|
|
|
This can cause problems - for example, if the link has negotiated a
|
|
different set of operating parameters, these will not be communicated
|
|
to the MAC as the PHY state machine will still think that the link has
|
|
remained active.
|
|
|
|
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
|
|
---
|
|
|
|
--- a/drivers/net/phy/phy-c45.c
|
|
+++ b/drivers/net/phy/phy-c45.c
|
|
@@ -143,12 +143,9 @@ int genphy_c45_read_link(struct phy_devi
|
|
devad = __ffs(mmd_mask);
|
|
mmd_mask &= ~BIT(devad);
|
|
|
|
- val = phy_read_mmd(phydev, devad, MDIO_STAT1);
|
|
- if (val < 0)
|
|
- return val;
|
|
-
|
|
- /* Read twice because link state is latched and a
|
|
- * read moves the current state into the register
|
|
+ /* The link state is latched low so that momentary link
|
|
+ * drops can be detected. Do not double-read the status
|
|
+ * register if the link is down.
|
|
*/
|
|
val = phy_read_mmd(phydev, devad, MDIO_STAT1);
|
|
if (val < 0)
|