From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-184.mta0.migadu.com (out-184.mta0.migadu.com [91.218.175.184]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D36139EB59 for ; Wed, 29 Jul 2026 09:17:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785316639; cv=none; b=gO9XJc9oH6DdfK1Bjidhhr/bCgQcZh+ykyj23LrKbZVWRvko4XVBlBfOqz1tApPRsvkhK906F0Cd7L3MgjHEzFKkwrDYss38Ir+DgEmOr5wX0gvwW2VcrGwnpVwXANmRzzBj1v4hofbI6uSIKECpLvG6X44ek+rU3LEtjDIY2vg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785316639; c=relaxed/simple; bh=xPi4Rv8XyiGFZvx2zQ3gRlsuHHPzhPGuzz9AHq/zRgo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=KsKwPXieZSKEQYCDN+JrkGGQs2Fp1/OglKn7oN2Ty5PjCuqbSbWxNBgJ0Jn+N3UKF9D+7qF8P/ZLRMnbw+l96GRHXfs33TKFIU/hzpIMXP0bF7ljAyAtvRVZwrJGqehHDxCKGtZa/LBR44Mld5TBe4zKgPJwuyC8AD+AXEb8kDk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=X8nPK6SL; arc=none smtp.client-ip=91.218.175.184 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="X8nPK6SL" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1785316633; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gS9b9/29h4glEuyPhOv6fnYDYfTo9zKm2g6AHt+PlKc=; b=X8nPK6SLDuaDBCPtkYqJ2vd2UjWvagyggaPA8YOx2o8y3dVmEmlS5OqdKrGYZox87JN5gu UtKSrDnYanyZXJwpji8zOfEirkmBoBW2wVagMeZsdGJKIIiPcOUp7CnvhORoXHa99lH33G 56nc57NYdMK2eLCsZAXs0R64kuOAGMs= Date: Wed, 29 Jul 2026 17:17:05 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH net-next v2] net: stmmac: dwxgmac2: configure INTM for per-channel interrupt routing To: Zxyan Zhu , Andrew Lunn , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Maxime Chevallier , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260729023653.1162763-1-zxyan0222@gmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qingfang Deng In-Reply-To: <20260729023653.1162763-1-zxyan0222@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2026/7/29 10:36, Zxyan Zhu wrote: > The XGMAC DMA_MODE register has an INTM field (bits 13:12) that > controls interrupt routing behavior for DMA transfer completion > events: > > 00 (default): sbd_perch_* are pulse signals, sbd_intr_o is also > asserted for each completion event. > 01: sbd_perch_* are level signals, sbd_intr_o is NOT > asserted for packet transfer completion events. > > When multi-MSI is enabled, per-channel TX/RX interrupts are expected > to arrive on their dedicated lines. In the default INTM=00 mode, > sbd_intr_o also fires for DMA completion events, but the multi-MSI > handler stmmac_mac_interrupt() only processes MAC-layer events (LPI, > PMT, timestamps) and returns IRQ_NONE for every DMA completion > interrupt, resulting in a continuous stream of unhandled interrupts > on the common IRQ. > > Hardware verification with XGMAC and multi-MSI enabled: > > INTM=00: 5.4 million common IRQ interrupts in 3 seconds, ~1.8 > million IRQ_NONE returns per second. > INTM=01: 0 common IRQ interrupts, per-channel IRQs work normally, > 10G line rate works correctly. > > Set INTM to mode 1 when multi-MSI is enabled. This matches the > existing GMAC4 implementation. > > XGMAC multi-MSI has never worked correctly since it was introduced. > > Signed-off-by: Zxyan Zhu As someone who has written an out-of-tree driver for the DW XGMAC: Reviewed-by: Qingfang Deng