[PATCH net] net: ethernet: mtk_eth_soc: fix RX data corruption issue

[Vladimir Oltean]

On Sat, Mar 04, 2023 at 01:43:20PM +0000, Daniel Golle wrote:
> Fix data corruption issue with SerDes connected PHYs operating at 1.25
> Gbps speed where we could previously observe about 30% packet loss while
> the bad packet counter was increasing.
> 
> As almost all boards with MediaTek MT7622 or MT7986 use either the MT7531
> switch IC operating at 3.125Gbps SerDes rate or single-port PHYs using
> rate-adaptation to 2500Base-X mode, this issue only got exposed now when
> we started trying to use SFP modules operating with 1.25 Gbps with the
> BananaPi R3 board.
> 
> The fix is to set bit 12 which disables the RX FIFO clear function when
> setting up MAC MCR, MediaTek SDK did the same change stating:
> "If without this patch, kernel might receive invalid packets that are
> corrupted by GMAC."[1]
> 
> [1]: https://git01.mediatek.com/plugins/gitiles/openwrt/feeds/mtk-openwrt-feeds/+/d8a2975939a12686c4a95c40db21efdc3f821f63
> 
> Fixes: 42c03844e93d ("net-next: mediatek: add support for MediaTek MT7622 SoC")
> Tested-by: Bjørn Mork <bjorn at mork.no>
> Signed-off-by: Daniel Golle <daniel at makrotopia.org>
> ---

I don't see something particularly controversial with this change.

Reviewed-by: Vladimir Oltean <olteanv at gmail.com>