Re: [PATCH v2 08/20] net/txgbe: fix link flow control registers for Amber-Lite

[Stephen Hemminger <stephen@networkplumber.org>]

On Wed, 29 Apr 2026 18:25:02 +0800
Zaiyu Wang <zaiyuwang@trustnetic.com> wrote:

> The flow control counter registers on AML NICs differ from those on SP
> NICs. Update the register offsets accordingly to ensure the counters
> work correctly.
> 
> Fixes: fb6eb170dfa2 ("net/txgbe: add basic link configuration for Amber-Lite")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Zaiyu Wang <zaiyuwang@trustnetic.com>
> ---

AI review warning:

Warning: txgbe_ethdev.c, in the AML branch added in txgbe_read_stats_registers(), uses assignment instead of accumulation:


if (hw->mac.type == txgbe_mac_aml || hw->mac.type == txgbe_mac_aml40) {
	hw_stats->rx_xon_packets = rd32(hw, TXGBE_PBRXLNKXON_AML);
	hw_stats->rx_xoff_packets = rd32(hw, TXGBE_PBRXLNKXOFF_AML);
} else {
	hw_stats->rx_xon_packets += rd32(hw, TXGBE_PBRXLNKXON);
The AML registers are write-clearable (cleared with wr32(reg, 0) in txgbe_clear_hw_cntrs) rather than read-on-clear. Reads return the absolute count from the hardware. txgbe_dev_stats_reset() zeros hw_stats but does not clear the hardware register, so on the next stats_get() the counters will jump back to the absolute hardware value rather than restarting from zero. The AML path needs the same offset-tracking pattern that UPDATE_QP_COUNTER_32bit uses (or the AML registers need to be cleared in stats_reset).