From: Chwee-Lin Choong Date: Thu, 4 Dec 2025 12:21:50 +0000 (+0800) Subject: igc: Reduce TSN TX packet buffer from 7KB to 5KB per queue X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8ad1b6c1e63d25f5465b7a8aa403bdcee84b86f9;p=thirdparty%2Fkernel%2Flinux.git igc: Reduce TSN TX packet buffer from 7KB to 5KB per queue The previous 7 KB per queue caused TX unit hangs under heavy timestamping load. Reducing to 5 KB avoids these hangs and matches the TSN recommendation in I225/I226 SW User Manual Section 7.5.4. The 8 KB "freed" by this change is currently unused. This reduction is not expected to impact throughput, as the i226 is PCIe-limited for small TSN packets rather than TX-buffer-limited. Fixes: 0d58cdc902da ("igc: optimize TX packet buffer utilization for TSN mode") Reported-by: Zdenek Bouska Closes: https://lore.kernel.org/netdev/AS1PR10MB5675DBFE7CE5F2A9336ABFA4EBEAA@AS1PR10MB5675.EURPRD10.PROD.OUTLOOK.COM/ Reviewed-by: Paul Menzel Reviewed-by: Simon Horman Reviewed-by: Aleksandr Loktionov Signed-off-by: Chwee-Lin Choong Tested-by: Avigail Dahan Signed-off-by: Tony Nguyen --- 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 */