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SubjectRe: [Intel-wired-lan] [PATCH] e1000e: fix timing for 82579 Gigabit Ethernet controller
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On 2/26/2017 11:08, Neftin, Sasha wrote:
> On 2/19/2017 14:55, Neftin, Sasha wrote:
>> On 2/16/2017 20:42, Bernd Faust wrote:
>>> After an upgrade to Linux kernel v4.x the hardware timestamps of the
>>> 82579 Gigabit Ethernet Controller are different than expected.
>>> The values that are being read are almost four times as big as before
>>> the kernel upgrade.
>>>
>>> The difference is that after the upgrade the driver sets the clock
>>> frequency to 25MHz, where before the upgrade it was set to 96MHz. Intel
>>> confirmed that the correct frequency for this network adapter is 96MHz.
>>>
>>> Signed-off-by: Bernd Faust <berndfaust@gmail.com>
>>> ---
>>> drivers/net/ethernet/intel/e1000e/netdev.c | 6 ++++++
>>> 1 file changed, 6 insertions(+)
>>>
>>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
>>> b/drivers/net/ethernet/intel/e1000e/netdev.c
>>> index 7017281..8b7113d 100644
>>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
>>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>>> @@ -3511,6 +3511,12 @@ s32 e1000e_get_base_timinca(struct
>>> e1000_adapter *adapter, u32 *timinca)
>>>
>>> switch (hw->mac.type) {
>>> case e1000_pch2lan:
>>> + /* Stable 96MHz frequency */
>>> + incperiod = INCPERIOD_96MHz;
>>> + incvalue = INCVALUE_96MHz;
>>> + shift = INCVALUE_SHIFT_96MHz;
>>> + adapter->cc.shift = shift + INCPERIOD_SHIFT_96MHz;
>>> + break;
>>> case e1000_pch_lpt:
>>> if (er32(TSYNCRXCTL) & E1000_TSYNCRXCTL_SYSCFI) {
>>> /* Stable 96MHz frequency */
>>> --
>>> 2.7.4
>>> _______________________________________________
>>> Intel-wired-lan mailing list
>>> Intel-wired-lan@lists.osuosl.org
>>> http://lists.osuosl.org/mailman/listinfo/intel-wired-lan
>>
>> Hello,
>>
>> e1000_pch2lan mac type corresponds to 82579LM and 82579V network
>> adapters. System clock frequency indication (SYSCFI) for these
>> devices supports both 25MHz and 96MHz frequency. By default
>> TSYNCRXCTL.SYSCFI is set to 1 and that means 96MHz frequency is picked.
>>
>> It is better to keep the current implementation as it covers all
>> options.
>>
>> Thanks,
>>
>> Sasha
>>
> Hello,
>
> During last couple of weeks I saw few complaints from community on
> same timing problem with 82579. I will double check clock definition
> with HW architecture.
>
> Sasha
>
> _______________________________________________
> Intel-wired-lan mailing list
> Intel-wired-lan@lists.osuosl.org
> http://lists.osuosl.org/mailman/listinfo/intel-wired-lan

I've double checked - 82579 support 96MHz frequency only. So, let's
accept this suggestion to upstream.

Ack.


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