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 --- v1: https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20250918183811.31270-1-chwee.lin.choong@intel.com/ changelog: v1 -> v2 - Elaborated commit message --- 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