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net: phy: lan87xx: Decrease phy polling rate

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Polling at 100Hz for 1.5s consumes quite a bit of kworker time with no
obvious benefit. Reduce that polling rate to ~6Hz.

To further save CPU and power, defer the next poll if no energy is
detected.

See: https://github.com/raspberrypi/linux/issues/4780

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
This commit is contained in:
Phil Elwell
2022-02-03 15:51:41 +00:00
parent 1bbae89303
commit b0272c695e
1 changed files with 9 additions and 1 deletions
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10
drivers/net/phy/smsc.c
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@@ -185,6 +185,8 @@ static int lan87xx_read_status(struct phy_device *phydev)
int err = genphy_read_status(phydev);
if (!phydev->link && priv->energy_enable) {
int energy_detected;
/* Disable EDPD to wake up PHY */
int rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);
if (rc < 0)
@@ -200,7 +202,7 @@ static int lan87xx_read_status(struct phy_device *phydev)
*/
read_poll_timeout(phy_read, rc,
rc & MII_LAN83C185_ENERGYON || rc < 0,
10000, 1500000, true, phydev,
150000, 1500000, true, phydev,
MII_LAN83C185_CTRL_STATUS);
if (rc < 0)
return rc;
@@ -210,10 +212,16 @@ static int lan87xx_read_status(struct phy_device *phydev)
if (rc < 0)
return rc;
energy_detected = !!(rc & MII_LAN83C185_ENERGYON);
rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,
rc | MII_LAN83C185_EDPWRDOWN);
if (rc < 0)
return rc;
/* Save CPU and power by deferring the next poll */
if (!energy_detected)
msleep(2000);
}
return err;