Bug 280810

Summary: igc(4) - include reference to intel i226 in man page -- review RSS
Product: Documentation Reporter: Eric <erichanskrs>
Component: Manual PagesAssignee: freebsd-bugs (Nobody) <bugs>
Status: New ---    
Severity: Affects Some People CC: doc, ziaee
Priority: ---    
Version: Latest   
Hardware: Any   
OS: Any   

Description Eric 2024-08-13 23:08:11 UTC 
I request that igc(4) be updated to include a reference to the intel i226.

It seems that Intel i226 chips are supported by the igc(4) driver*

As there is currently growing interest in 2.5G support for FreeBSD,
it would help FreeBSD users if the relevant I226-* chips are explicitly mentioned in igc(4)


For the following currently supported FreeBSD versions, including -CURRENT,
igc(4) does not mention the intel i226 nic. In the HARDWARE section it only lists i225 chips:
https://cgit.freebsd.org/src/tree/share/man/man4/igc.4

https://cgit.freebsd.org/src/tree/share/man/man4/igc.4?h=stable%2F13
https://cgit.freebsd.org/src/tree/share/man/man4/igc.4?h=releng%2F13.3
https://cgit.freebsd.org/src/tree/share/man/man4/igc.4?h=releng%2F13.4

https://cgit.freebsd.org/src/tree/share/man/man4/igc.4?h=stable%2F14
https://cgit.freebsd.org/src/tree/share/man/man4/igc.4?h=releng%2F14.0
https://cgit.freebsd.org/src/tree/share/man/man4/igc.4?h=releng%2F14.1


___
* Based on the Product brief Intel i225/i226
https://cdrdv2.intel.com/v1/dl/getContent/621753
one distinguishing difference is the support for RSS:
"Receive Side Scaling (RSS) (I226 only)"

https://github.com/freebsd/freebsd-src/blob/releng/14.1/sys/dev/igc/if_igc.c#L40-L70
references the i226 IGC_DEV_ID_I226_* id's

Based on
https://github.com/freebsd/freebsd-src/blob/releng/14.1/sys/dev/igc/if_igc.c#L1388
and various other RSS references it looks like the i226 is actively supported by FreeBSD.

Notably: although the i225 is explicitly mentioned in the 14.1 Hardware Notes for igc(4):
https://www.freebsd.org/releases/14.1R/hardware/
the i226 is not mentioned.
Comment 1 Eric 2024-08-13 23:29:57 UTC 
If applicable, remove RSS support for i225 in igc(4).

Product brief Intel i225/i226
https://cdrdv2.intel.com/v1/dl/getContent/621753
"Receive Side Scaling (RSS) (I226 only)"

However, igc(4) suggests the i225 does supports RSS:
DESCRIPTION
       The igc driver provides support for any PCI Express adapter or LOM (LAN
       On  Motherboard)	based on the Intel I225	Multi Gigabit Controller.  The
       driver  supports	 Transmit/Receive  checksum  offload,  Jumbo   Frames,
       MSI/MSI-X, TSO, and RSS.

Please clarify this contradiction wrt RSS.

If RSS is indeed not present in i225, please discriminate RSS support:
i225 - NO RSS support
i226 - supports RSS
Comment 2 Alexander Ziaee freebsd_triage 2024-08-22 21:38:21 UTC 
I have some time and bandwidth, I am willing to work on this issue.