From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (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 CD5F9398900 for ; Thu, 12 Mar 2026 04:44:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773290660; cv=none; b=IBAKFltqfqrlFwiVPS868RlNqRUuG+mcJCpmClDelg+7VPNhQWq4vPrY0qp0dNB6lOujVnFfrgMTBuIJEnWrV3Jp87s2HjY8rlSrKoUHbxknw57MLwHbwEhKkvM+HGuvpbAwHZIKhuKUlMrGyAOcng14nsaEQYDcjnWj1IGakv4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773290660; c=relaxed/simple; bh=2O77vFYxe4s139LG3le5/bTujuAyznMsAswt0RlaFLI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=k4vxax4l2CHSuN+hZ5LfRffGz61QHiT41upL8OW/M3Q+YI6jxjhQ3e4hl79OTTnoZL4W0e6i6idj6j7RZdB+hGLd0PfMWoHuu3cKp86UeWJlKcj/D429kYKxNAjubH680++zWkAV+8FCt7egtMwCS2YZgNRE4kN59iNxNcl279g= 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=Fq3GvbNQ; arc=none smtp.client-ip=95.215.58.174 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="Fq3GvbNQ" Message-ID: <5e488437-68eb-43e9-a774-babea5879e4a@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1773290657; 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=J7qIC1KY9FFhtX93qUfzvqKXNfPgZFHBgtjBMwn299Y=; b=Fq3GvbNQtO+qm+FlZQnykfJDdiv8/JsnLy/MvO+RFaO4AQgkAgJgtfKF1OrCf3+1XPhs8q ZBP7IvcKjSxirdm6YPCLkuSaZpha1G12VAceEycyOM6u+Ia3Ohll1ns0513YH0RBDj1T/Y 9SfZv/TZg3n2/KdVUNUxV47axK6JKzs= Date: Wed, 11 Mar 2026 21:34:43 -0700 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] soundwire: cadence: Clear message complete before signaling waiting thread To: Richard Fitzgerald , vkoul@kernel.org, yung-chuan.liao@linux.intel.com Cc: linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, patches@opensource.cirrus.com References: <20260310113133.1707288-1-rf@opensource.cirrus.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Pierre-Louis Bossart In-Reply-To: <20260310113133.1707288-1-rf@opensource.cirrus.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 3/10/26 04:31, Richard Fitzgerald wrote: > Clear the CDNS_MCP_INT_RX_WL interrupt before signaling completion. > > This is to prevent the potential race where: > - The main thread is scheduled immediately the completion is signaled, > and starts a new message > - The RX_WL IRQ for this new message happens before sdw_cdns_irq() has > been re-scheduled. > - When sdw_cdns_irq() is re-scheduled it clears the new RX_WL interrupt. > > MAIN THREAD | IRQ THREAD > | > _cdns_xfer_msg() | > { | > write data to FIFO | > wait_for_completion_timeout() | > | <---- RX_WL IRQ > | sdw_cdns_irq() > | { > | signal completion > <== RESCHEDULE <== > Handle message completion | > } | > | > Start new message | > _cdns_xfer_msg() | > { | > write data to FIFO | > wait_for_completion_timeout() | > | <---- RX_WL IRQ > ==> RESCHEDULE ==> > | // New RX_WL IRQ is cleared before > | // it has been handled. > | clear CDNS_MCP_INTSTAT > > | return IRQ_HANDLED; > | } > > Before this change, this error message was sometimes seen on kernels > that have large amounts of debugging enabled: > > SCP Msg trf timed out > > This error indicates that the completion has not been signalled after > 500ms. > > Signed-off-by: Richard Fitzgerald > Fixes: 956baa1992f9 ("soundwire: cdns: Add sdw_master_ops and IO transfer support") > Reported-by: Norman Bintang > Closes: https://issuetracker.google.com/issues/477099834 Makes sense to me, nice fix! Reviewed-by: Pierre-Louis Bossart > --- > drivers/soundwire/cadence_master.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c > index f245c3ffb9e9..b8b62735c893 100644 > --- a/drivers/soundwire/cadence_master.c > +++ b/drivers/soundwire/cadence_master.c > @@ -933,6 +933,14 @@ irqreturn_t sdw_cdns_irq(int irq, void *dev_id) > > cdns_read_response(cdns); > > + /* > + * Clear interrupt before signalling the completion to avoid > + * a race between this thread and the main thread starting > + * another TX. > + */ > + cdns_writel(cdns, CDNS_MCP_INTSTAT, CDNS_MCP_INT_RX_WL); > + int_status &= ~CDNS_MCP_INT_RX_WL; > + > if (defer && defer->msg) { > cdns_fill_msg_resp(cdns, defer->msg, > defer->length, 0);