e1000: Disable FC pause time on PCH2 and newer
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Authored by kbowling on Jan 6 2026, 10:13 AM.

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Intel Networking
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rG2bdec2ee73be: e1000: Increase FC pause/refresh time on PCH2 and newer

Summary

This corresponds to Linux f74dc880098b4a29f76d756b888fb31d81ad9a0c.

That commit does not provide any public background detail, but it's been
in use for over 5 years and corresponds to previous chip bugs disabling
automatic generation of PAUSE frames.

MFC after:      2 weeks

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rG FreeBSD src repository

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kbowling created this revision.Jan 6 2026, 10:13 AM

Owners added a reviewer: Restricted Owners Package.Jan 6 2026, 10:13 AM

Herald added a subscriber: imp. · View Herald TranscriptJan 6 2026, 10:13 AM

kbowling requested review of this revision.Jan 6 2026, 10:13 AM

I wasn't able to find any additional info about a reason for this change, but I agree that 5+ years is enough time to assume it makes sense.

I don't think though that it disables FC pause time completely. In my understanding with this change XOFF frames will have quanta value set to 0xFFFF, and the time before next XOFF frame is sent will be increased to maximum. This may prevent blocking link partner TX path for too long.

This revision is now accepted and ready to land.Thu, Feb 12, 9:51 AM

Closed by commit rG2bdec2ee73be: e1000: Increase FC pause/refresh time on PCH2 and newer (authored by Kevin Bowling <kbowling@FreeBSD.org>). · Explain WhyFri, Feb 13, 6:35 AM

This revision was automatically updated to reflect the committed changes.

Kevin Bowling <kbowling@FreeBSD.org> added a commit: rG2bdec2ee73be: e1000: Increase FC pause/refresh time on PCH2 and newer.