From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793888799; b=gCB/NX2hWeUohIQCUHUxwhSaHdbQgt/n3P9nOHkRhhMJwy4kiZIqtlnkN0XuwOeEaxpO ej93pInw7USQqOfvTcmdUaaocd7NFW1DYVlwtMgb10O7//WRVvnn+obDS6M6dmBGokini idaTzq04ny7b5REpuZ+90WS0h8aoFJbIi4XKpbdekGKzwoIGEClZgvbJNpTH/Dhr2t7si HJeFCsWcOVQYyM6yW5wqJoB6bCT9BWRv2sGozI+6FcdBqUMk2oNic+GP9BV8NRopzWzOZ Yeogn9AobwvkYpMA6Wz8JfLK9JwN1m0yEvX7lhuqHk/zCjHzI5z0Nta+TEXoW3+l8eQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793888799; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=bB115A0rMOTqlvXkN/AIzQNgK8qZfXA7IorSb9CX7io=; b=BIR8JXWGPAL/WArjmZnRttenKxLleXQH3P3l+3H/MvWSQ1hjWMuSjj5isCPI8CaJQjEW f5YiBr26Q8VvOvoU5HZMCQjlACUTGIOJ1oVYQgwTn4XrrgbrI0Gz8bWmOj8gGw0Pu/xgn +UGmF/4bCR/oWCJa1xz5K2z1aPdJl1KE0QYbHdXBc4DDmvywWtiDvKhGvQ3BRm8SSP+Mm 3fTazK0Jw0JFzjJ53lkJnqZ8L2G4YFkkHhw1gPaH2J7zsYJQprykpM3B7AHtq1QcPcXN9 cRfzN9uRUUY6OgJqRpy8ckDQhfZxV/6wDgTmIHmZAqkGvLAHSDgOp6hRwy0fvzEJ0MQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=kLZbEpUR; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C6908606A32D; Thu, 5 Nov 2026 14:26:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=kLZbEpUR Received: by smtp.kernel.org (Postfix) with ESMTPSA id 141081F000C1; 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-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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