[PATCH] net/ixgbe: fix DCB Rx buffer size on X540 and E610

[Bruce Richardson]

On Sun, Sep 27, 2026 at 12:59:43PM +0800, Zhang Tengfei wrote:
> DCB programs RXPBSIZE from a hardcoded total, 384 KB for X550
> and 512 KB for every other MAC. The base driver records 384 KB
> in hw->mac.rx_pb_size for X540, and E610 inherits that through
> the X540 init ops. X540 and E610 reset also write 384 KB.
> 
> Use hw->mac.rx_pb_size for the split, including the PFC
> watermarks derived from it. 82598, 82599 and X550 are unchanged.
> 
> Fixes: b7fcd13c90a3 ("ixgbe: fix X550 DCB")
> Fixes: 316637762a5f ("net/ixgbe/base: enable E610 device")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Zhang Tengfei <zhtfdev at gmail.com>
> ---
>  drivers/net/intel/ixgbe/ixgbe_rxtx.c | 27 ++++-----------------------
>  1 file changed, 4 insertions(+), 23 deletions(-)
> 

Acked-by: Bruce Richardson <bruce.richardson at intel.com>

Applied to dpdk-next-net-intel. Thanks.
I've also squashed patch [1] into this commit, so that we have your name
correctly reported in .mailmap for this, and that check-git-log script
doesn't complain. Any issues with me doing so, please let me know.

Thanks,
/Bruce

[1] https://patches.dpdk.org/project/dpdk/patch/20260927035949.36887-1-zhtfdev@gmail.com/

> diff --git a/drivers/net/intel/ixgbe/ixgbe_rxtx.c b/drivers/net/intel/ixgbe/ixgbe_rxtx.c
> index 60222693fe..890289f27f 100644
> --- a/drivers/net/intel/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/intel/ixgbe/ixgbe_rxtx.c
> @@ -3835,8 +3835,6 @@ ixgbe_rss_configure(struct rte_eth_dev *dev)
>  }
>  
>  #define NUM_VFTA_REGISTERS 128
> -#define NIC_RX_BUFFER_SIZE 0x200
> -#define X550_RX_BUFFER_SIZE 0x180
>  
>  static void
>  ixgbe_vmdq_dcb_configure(struct rte_eth_dev *dev)
> @@ -3863,18 +3861,10 @@ ixgbe_vmdq_dcb_configure(struct rte_eth_dev *dev)
>  
>  	/*
>  	 * RXPBSIZE
> -	 * split rx buffer up into sections, each for 1 traffic class
> +	 * Split the MAC Rx packet buffer equally across traffic classes.
> +	 * hw->mac.rx_pb_size is the total size in KB.
>  	 */
> -	switch (hw->mac.type) {
> -	case ixgbe_mac_X550:
> -	case ixgbe_mac_X550EM_x:
> -	case ixgbe_mac_X550EM_a:
> -		pbsize = (uint16_t)(X550_RX_BUFFER_SIZE / nb_tcs);
> -		break;
> -	default:
> -		pbsize = (uint16_t)(NIC_RX_BUFFER_SIZE / nb_tcs);
> -		break;
> -	}
> +	pbsize = (uint16_t)(hw->mac.rx_pb_size / nb_tcs);
>  	for (i = 0; i < nb_tcs; i++) {
>  		uint32_t rxpbsize = IXGBE_READ_REG(hw, IXGBE_RXPBSIZE(i));
>  
> @@ -4394,16 +4384,7 @@ ixgbe_dcb_hw_configure(struct rte_eth_dev *dev,
>  		}
>  	}
>  
> -	switch (hw->mac.type) {
> -	case ixgbe_mac_X550:
> -	case ixgbe_mac_X550EM_x:
> -	case ixgbe_mac_X550EM_a:
> -		rx_buffer_size = X550_RX_BUFFER_SIZE;
> -		break;
> -	default:
> -		rx_buffer_size = NIC_RX_BUFFER_SIZE;
> -		break;
> -	}
> +	rx_buffer_size = (uint16_t)hw->mac.rx_pb_size;
>  
>  	if (config_dcb_rx) {
>  		/* Set RX buffer size */
> -- 
> 2.53.0
>