net: mv643xx_eth: ensure coalesce settings survive read-modify-write

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The coalesce settings behave badly when changing just one value:

... # ethtool -c eth0
rx-usecs: 249
... # ethtool -C eth0 tx-usecs 250
... # ethtool -c eth0
rx-usecs: 248

This occurs due to rounding errors when calculating the microseconds
value - the divisons round down.  This causes (eg) the rx-usecs to
decrease by one every time the tx-usecs value is set as per the above.

Fix this by making the divison round-to-nearest.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

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Russell King 2016-11-01 10:50:01 +00:00 • committed by David S. Miller

parent 42fb18fd58

commit b9b84fc07d

1 changed files with 2 additions and 0 deletions

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drivers/net/ethernet/marvell/mv643xx_eth.c

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