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=1792773741; b=jI+W9PUPoCuH+rAB479bauxdcSG6pxtvjYyWTg+N8ezU31TE9R/QJPjLtDo1k4mdpftv H3MgNjweL0YiBOuAVmpV4sQBEtPI7khs3jkhmmbCH96r8OlxjeJk/nrX3nXzAo+SRxEJT DGRvXQy2fGJA6lwrRf4v89KHDHpUQduzwKbznq13e3S04FRBDHj15NUjM3W5e0mLrfyCa g4ow1OmNdqDMjVTuXyajV6Qv6dNX/5W/siNzVPwzMHa71tchgalhgIN4MJnaNwg1qOkfq mJsUrw69WzYgPR3iYiNSO8SSQc42o0XIRGnIGthm69tEYsXdzTxe0EX5HRGe/86em/w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792773741; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=qAfXxOG6/edrVZDI7/p7NU6pSaMJKb41wm48epIIO7k=; b=yoNcJaBOe9T2iHE7y72XTlUuGZokp4/qHb6d+EQ1VoLgMvAkvAfgZJFZhb3oMGekYscq Ji8JTMKIdkO0qoozKA0qAA6/MHlwYJ3WEv0zz6fA8s0xWCQ9zbrPrB8u3xFQAJOI4shlr WnS5TMdbEfaLhl8G1bjojDbGv5oS5kh/3n8tlf0KjyuaeCOr0t0pp8Kij35JbJevaA076 NTl+XlVbgqGqFsnR6G+9LCBzjqUvDRPwkYIpD6veVvi/3TCDvadX4kVXswzZxh+dQ/veA beoIqpUpF4yzqRdAaP2Jc8vcHrThWufasv2IuaB3UpoC3NRtMXfIkmgsF1A/Gk0VTww== 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=KuGX04R2; 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 77334606A31A for ; Fri, 23 Oct 2026 16:42:21 +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=KuGX04R2 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 366461F01825; Fri, 23 Oct 2026 16:42:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792773741; bh=qAfXxOG6/edrVZDI7/p7NU6pSaMJKb41wm48epIIO7k=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=KuGX04R27LaqPeklmmdj6x+cGoHSeJmfn51sA2i0qonISK2RF2GcRKvVbjKIt//h7 EwN/+6F8mjOJOk1MM1J96bVZrx11aK2CLjMUqA50YFVTbg+I3aYq6hqw2Wf3SRL5dn iPEqvPXsT4OELsr6vqCBVSznHx2wk1xPlvZBLq9nvDro2EOv2BTHl+PQtRTu0OnT9h MMvCnb+QUYTuZnT5C9Df2O/v8+jA0Rni94T86ntpPOq1+UOwXc2Zz3Ml3cSoDxirck o6uTYBZ7uSCJ97qtmIymJ/EuE6NjrInf68Ybp1AKgFfTeUQGbDb8DUClIlPVN7O//1 MJ0iOFLkKOexw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 1/4] dmaengine: dw: Fix XFER bit set, but channel not idle error Reply-To: sashiko-reviews@lists.linux.dev To: "James Hilliard" Cc: linux-serial@vger.kernel.org In-Reply-To: <20261023-submit-dw-dma-synchronize-v1-v3-1-c62bf048f5ce@gmail.com> References: <20261023-submit-dw-dma-synchronize-v1-v3-0-c62bf048f5ce@gmail.com> <20261023-submit-dw-dma-synchronize-v1-v3-1-c62bf048f5ce@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 23 Oct 2026 16:42:20 +0000 X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > From: Serge Semin >=20 > If a client driver gets to use the DW DMAC engine device tougher > than usual, with occasional DMA-transfers termination and restart, then > the next error can be randomly spotted in the system log: >=20 > > dma dma0chan0: BUG: XFER bit set, but channel not idle! >=20 > For instance that happens in case of the 8250 UART port driver handling > the looped back high-speed traffic (in my case > 1.5Mbaud) by means of the > DMA-engine interface. >=20 > The error happens due to the two-staged nature of the DW DMAC IRQs > handling procedure and due to the critical section break in the meantime. > In particular in case if the DMA-transfer is terminated and restarted: > [ ... ] > Fixes: 3bfb1d20b547 ("dmaengine: Driver for the Synopsys DesignWare DMA c= ontroller") > Cc: stable@vger.kernel.org > Signed-off-by: Serge Semin > [james: require a locked XFER event and handle an empty active list] > Signed-off-by: James Hilliard Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261023-submit-dw-= dma-synchronize-v1-v3-0-c62bf048f5ce@gmail.com?part=3D1