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=1793313592; b=5fy1h5fhN1f1B3U/Dq7RK2mPih42r/f8rGKm3L7QoeH2kCiE8D4euInTfcZ0wie8yVIH 9cUxGHj8+DWVxKPzd1TAjLcQ6V2YPGvcQiZAeiJq0BRuCSzCZipLoHT9si8WgDsju32KJ X4wPLcudastIWZi8jb8Gwy6zGeFSRTfqaHCf10f+NJZMG5mcAS7KmYl0atIQrv/S8uToz He7Xmc3fg0q+1NP6GdmhhCtEk7NGrAjnXMTGhYVK0YACryUwSu/8SY3+SyHOJWjiMpGLV x9QrBkcYMuZ1juOV5biXXuB/tCD6Pktpf/HUfNtUn2uutalrHnyj5fxPksGF5I15XPw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793313592; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=zQ6uNo89nejCaAU7k5tj/9f4wgEOYJASxK8zmXwc9nE=; b=HHFxuW5CHSkRd9HQJoo2vPT+ScDZj3WzJ7FH+SowygBjFQE8JuwRVlG9b+DXBSGQXuRh 9BlPc2UlMHifjiU0MjH9QMkl6cxIY1dg3qVorKRFr4Ot5GnMTPpRdvwIcHwjEcMjNOCIX cpR4K9Bia0UdUBkWTgQkt5sEU9XnPv0fKFGlE06CQZ+319mtbzB3efIxtEouMC2IbNGd8 lxH7/pPde78jg0hMsi5RVhoE7dpIZFVni3qwvpKjaK8ozOuuP6mnvKZxjhD4QoDNRZpDa DrQ/RaoG34dNS2yXfMoVf5Rrfky7jiIPeNZ4l3wkrkOhdZ1OOLS5QpAsHSk79dE1cfQ== 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=HEeICKi1; 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 0DD9A606A31A for ; Thu, 29 Oct 2026 22:39:51 +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=HEeICKi1 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89DEE1F01816; Thu, 29 Oct 2026 22:39:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793313591; bh=zQ6uNo89nejCaAU7k5tj/9f4wgEOYJASxK8zmXwc9nE=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=HEeICKi1KAbTQJ38DCGz6ambIK5AMfL9ZGgREySTEy4nLdQhh00fXxiGrAirtykW9 LDPmotpdUSgW3Ddtp1BZn/cJdOiHh7xPRclpEwZFrdhYHpIbsjzztnpt/9k6gNYX2A Mbgr60Kp5vibfSBF7BWdiJCLCos8lxjHMgJCHen84DQglBHj6UXw8UItc/AAfhI+iF ST4MfCH0rqQwZPpXVduSJ9CVIRRdjC7t8ktilkCwThOctIETOquNzHpjH0O7qGo6QG 0BbcmkwHoVty+GJKepgxOlxAiKiQZDJnJ6uaz3D7qOs/OwzVMsLm+GLf0uNG6rItMY Fa4EjKRVA8K2Q== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 1/7] 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: <20261029-submit-dw-dma-synchronize-v1-v4-1-fea447d9f285@gmail.com> References: <20261029-submit-dw-dma-synchronize-v1-v4-0-fea447d9f285@gmail.com> <20261029-submit-dw-dma-synchronize-v1-v4-1-fea447d9f285@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 29 Oct 2026 22:39:51 +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/20261029-submit-dw-= dma-synchronize-v1-v4-0-fea447d9f285@gmail.com?part=3D1