Commit 75517d92 authored by Jiri Benc's avatar Jiri Benc Committed by Jeff Kirsher
Browse files

igb: fix PHC stopping on max freq

For 82576 MAC type, max_adj is reported as 1000000000 ppb. However, if
this value is passed to igb_ptp_adjfreq_82576, incvalue overflows out of
INCVALUE_82576_MASK, resulting in setting of zero TIMINCA.incvalue, stopping
the PHC (instead of going at twice the nominal speed).

Fix the advertised max_adj value to the largest value hardware can handle.
As there is no min_adj value available (-max_adj is used instead), this will
also prevent stopping the clock intentionally. It's probably not a big deal,
other igb MAC types don't support stopping the clock, either.
Signed-off-by: default avatarJiri Benc <>
Acked-by: default avatarMatthew Vick <>
Tested-by: default avatarAaron Brown <>
Signed-off-by: default avatarJeff Kirsher <>
parent 05ec29e8
......@@ -740,7 +740,7 @@ void igb_ptp_init(struct igb_adapter *adapter)
case e1000_82576:
snprintf(adapter->, 16, "%pm", netdev->dev_addr);
adapter->ptp_caps.owner = THIS_MODULE;
adapter->ptp_caps.max_adj = 1000000000;
adapter->ptp_caps.max_adj = 999999881;
adapter->ptp_caps.n_ext_ts = 0;
adapter->ptp_caps.pps = 0;
adapter->ptp_caps.adjfreq = igb_ptp_adjfreq_82576;
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