RE: [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet buffer per queue for TSN mode

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf
> Of Chwee-Lin Choong
> Sent: Tuesday, December 2, 2025 1:24 PM
> To: Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; Andrew Lunn
> <andrew+netdev@xxxxxxx>; David S . Miller <davem@xxxxxxxxxxxxx>; Eric
> Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo
> Abeni <pabeni@xxxxxxxxxx>
> Cc: intel-wired-lan@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Bouska; Bouska, Zdenek
> <zdenek.bouska@xxxxxxxxxxx>; Faizal Rahim
> <faizal.abdul.rahim@xxxxxxxxxxxxxxx>
> Subject: [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet
> buffer per queue for TSN mode
> 
> Update IGC_TXPBSIZE_TSN to allocate 5KB per TX queue (TXQ0-TXQ3) as
> recommended in I225/I226 SW User Manual Section 7.5.4 for TSN
> operation.
> 
> Fixes: 0d58cdc902da ("igc: optimize TX packet buffer utilization for
> TSN mode")
> Reported-by: Bouska, Zdenek <zdenek.bouska@xxxxxxxxxxx>
> Closes:
> https://lore.kernel.org/netdev/AS1PR10MB5675DBFE7CE5F2A9336ABFA4EBEAA@
> AS1PR10MB5675.EURPRD10.PROD.OUTLOOK.COM/
> Signed-off-by: Chwee-Lin Choong <chwee.lin.choong@xxxxxxxxx>
> ---
>  drivers/net/ethernet/intel/igc/igc_defines.h | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h
> b/drivers/net/ethernet/intel/igc/igc_defines.h
> index 498ba1522ca4..9482ab11f050 100644
> --- a/drivers/net/ethernet/intel/igc/igc_defines.h
> +++ b/drivers/net/ethernet/intel/igc/igc_defines.h
> @@ -443,9 +443,10 @@
>  #define IGC_TXPBSIZE_DEFAULT ( \
>  	IGC_TXPB0SIZE(20) | IGC_TXPB1SIZE(0) | IGC_TXPB2SIZE(0) | \
>  	IGC_TXPB3SIZE(0) | IGC_OS2BMCPBSIZE(4))
> +/* TSN value following I225/I226 SW User Manual Section 7.5.4 */
>  #define IGC_TXPBSIZE_TSN ( \
> -	IGC_TXPB0SIZE(7) | IGC_TXPB1SIZE(7) | IGC_TXPB2SIZE(7) | \
> -	IGC_TXPB3SIZE(7) | IGC_OS2BMCPBSIZE(4))
> +	IGC_TXPB0SIZE(5) | IGC_TXPB1SIZE(5) | IGC_TXPB2SIZE(5) | \
> +	IGC_TXPB3SIZE(5) | IGC_OS2BMCPBSIZE(4))
> 
>  #define IGC_DTXMXPKTSZ_TSN	0x19 /* 1600 bytes of max TX DMA packet
> size */
>  #define IGC_DTXMXPKTSZ_DEFAULT	0x98 /* 9728-byte Jumbo frames */
> --
> 2.43.0

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>