From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97548606A32C for ; Thu, 5 Nov 2026 14:26:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=V0+bNUdB; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=kLZbEpUR DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; 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Thu, 5 Nov 2026 14:26:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793888798; bh=bB115A0rMOTqlvXkN/AIzQNgK8qZfXA7IorSb9CX7io=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kLZbEpUR7tlo+ZWC3OftlZigeROV+G/S2MWiAUwnAhPdaCJM4iLo5A1awAhxavhsK ODjt8ZKDP88satnWbUD6GyJ4WG7eLo0fcKsRBdewiQXCYKDQoZBgmWtygUXii0VkeL ShvkzBiNtiL8sf6hl04MO5SbTW7/GJVdVyI1b/pui/+wRkbFAza9ODH+jrtyPohyka dbCoChO6ac7g5lWxqnMOdWvoT2FaIXl2YzLeZYbMMwkKpAJW7TTjS4qMR9oAGRctuP EXSy3J89Bl1d90+lV7gUPTfQ2Zb65/zQZiFuc8RLOnMhxIu49FPToTDTH59SakH3pB t2ru7Bf2Hxzuw== Date: Thu, 5 Nov 2026 14:26:34 +0000 From: Simon Horman To: Sandeep Haemoon Cc: netdev@vger.kernel.org, Felix Fietkau , Lorenzo Bianconi , linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next 1/2] net: ethernet: mtk_eth_soc: add 9K jumbo frame Message-ID: <20261105142634.GT865646@horms.kernel.org> References: X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Nov 02, 2026 at 12:48:45AM +0200, Sandeep Haemoon wrote: > The driver caps max_mtu at 2030 bytes and programs the MAC max-rx field > for at most 2048-byte frames, so MTU > 2K is rejected and 9K jumbo > frames are not usable on the 10G XGMII MACs. > > Add a MTK_NETSYS_RX_9K capability for MT7988 and: > - advertise 9K max_mtu on XGMII MACs, derived from the DT phy_mode at > probe time so DSA can raise the conduit MTU before the netdev is > opened; > - program XMAC_RX_CFG2 on the XGMII MACs; > - derive the shared RX buffer length from the largest MTU and size the > RX rings from it; > - program the PDMA RX SDL max frame so the DMA engine accepts jumbo > frames; > - reject a runtime MTU change that would need a different ring buffer > size while DMA is running; the rings are sized at the next open. > > This is a forward-port of the MediaTek downstream jumbo series: > Mason Chang's "change default rx buffer length", "add 9k jumbo frame > support" and "add dynamic rx buffer adjustment support" (MediaTek > OpenWrt feed 999-eth-30/31/33, carried in > frank-w/BPI-Router-Linux 92bfdbdd4de1/b4c6cb1d5532/ca4c976dce22), > plus Frank Wunderlich's "try to fix crash the right way" > (a3207a383794). > > Link: https://github.com/frank-w/BPI-Router-Linux/commit/b4c6cb1d5532 > Link: https://github.com/mediatek/mtk-openwrt-feeds > Signed-off-by: Sandeep Haemoon Reviewed-by: Simon Horman