From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F360F4718CA; Mon, 28 Sep 2026 08:49:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790585366; cv=none; b=uWufQQuIKqEu/CRGFSr6CtStXI8SGq5Ouh+4//0TtzxxxPw2Kll8X93IRz0RzoI7+Q2xLtV0oGzapiySYnvk4QNOUEI04jL5HkYu8agevWobBvdPTykLjS2hQgdAi3SYo8LDGKLGz9jrmYuhVNiK/7sBkLUEQHxQgD78o4p47Qo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790585366; c=relaxed/simple; bh=OfCLiohuhbyWMPoHKaQlg2T1gfW+pDj5nssHyA2+2pg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Irt04mTxW0krQcQRh8H94YhQ757ygCXY82zj81YaFbcFWDicAf0xuL9K0d1d5MpDxVppxFG5cnbxs4On/lfW7OH31aq+7vNKgPE8+9hZtNiQQOQHEodoXKSCPdOPjS3ApdQp4/N2WAre87tSc1ZSR+toymySfb42JeKBFgn/pqE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gnudo0Q1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gnudo0Q1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D59811F000FF; Mon, 28 Sep 2026 08:49:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790585364; bh=L8DvlVON08rYuMFKT7B6LMBAAtrayUN7D5me5i20LPQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=gnudo0Q1D/3j8j4/Jrc6CKrcxqLAdyJiiFu5/e6bOj2FkNNZDoGBNSGHjG0EfOABq CkhyvzEyDnCApeXo0eUD0QxlsHvZiTAjduHo/naqNQ7cD4mU7xAwXZWXXp500xWqRX rDnznmfUEbtOe4NonHkv6E+tdDF9F6yjxqoJ8pygiw6vjBK3+TbLBNXCd3XuFvrTYG /T7FdCLartfdsBNeG7AKGCCzOgYQtVOW69bfr+1+d7AX7v+qTcRExZArDZCtR72cpR oxXDOlg/rbquAPQSIOeNZfwdu8QjJXY5SHf9WV/6lfN8KdD8oE3px1djZcesui1Jgf KXlKfGqMdiQew== Message-ID: Date: Mon, 28 Sep 2026 09:49:20 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/5] media: qcom: camss: vfe: Fix VFE reset while another line is streaming To: Hitesh Patel , linux-media@vger.kernel.org Cc: Bryan O'Donoghue , Vladimir Zapolskiy , Loic Poulain , Mauro Carvalho Chehab , Gjorgji Rosikopulos , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, ravi@ebytelogic.com References: <20260928064336.272659-1-hitesh@ebytelogic.com> <20260928064336.272659-4-hitesh@ebytelogic.com> From: Bryan O'Donoghue Content-Language: en-GB Autocrypt: addr=bod@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 28/09/2026 07:43, Hitesh Patel wrote: > @@ -814,6 +814,7 @@ static int vfe_disable_output(struct vfe_line *line) > struct vfe_output *output = &line->output; > unsigned long flags; > unsigned int i; > + bool last; > > spin_lock_irqsave(&vfe->output_lock, flags); > for (i = 0; i < output->wm_num; i++) > @@ -821,6 +822,13 @@ static int vfe_disable_output(struct vfe_line *line) > output->gen2.active_num = 0; > spin_unlock_irqrestore(&vfe->output_lock, flags); > > + mutex_lock(&vfe->stream_lock); > + last = vfe->stream_count == 1; > + mutex_unlock(&vfe->stream_lock); > + > + if (!last) > + return 0; > + NAK. This can't be correct, in fact its very racy and will break. Here is the existing code. static int vfe_disable_output(struct vfe_line *line) { struct vfe_device *vfe = to_vfe(line); struct vfe_output *output = &line->output; unsigned long flags; unsigned int i; spin_lock_irqsave(&vfe->output_lock, flags); for (i = 0; i < output->wm_num; i++) vfe->res->hw_ops->vfe_wm_stop(vfe, output->wm_idx[i]); output->gen2.active_num = 0; spin_unlock_irqrestore(&vfe->output_lock, flags); return vfe_reset(vfe); } /* * vfe_disable - Disable streaming on VFE line * @line: VFE line * * Return 0 on success or a negative error code otherwise */ int vfe_disable(struct vfe_line *line) { struct vfe_device *vfe = to_vfe(line); int ret; ret = vfe_disable_output(line); if (ret) goto error; vfe_put_output(line); mutex_lock(&vfe->stream_lock); vfe->stream_count--; mutex_unlock(&vfe->stream_lock); error: return ret; } Here's how stream_count = 2; thread0: vfe_disable() vfe_disable_output() mutex_lock(); last = stream_count == 1; //false mutex_unlock(); return; thread1: vfe_disable() vfe_disable_output() mutex_lock(); last = stream_count == 1; //false mutex_unlock(); return; thread0: vfe_disable() mutex_lock(); stream_count--; // => stream_count = 1; mutex_unlock(); thread1: vfe_disable() mutex_lock(); stream_count--; // => stream_count = 0; mutex_unlock(); vfe_reset() is never called. this-> diff --git a/drivers/media/platform/qcom/camss/camss-vfe.c b/drivers/media/platform/qcom/camss/camss-vfe.c index 34e4319d8f80c..3dafd5d778630 100644 --- a/drivers/media/platform/qcom/camss/camss-vfe.c +++ b/drivers/media/platform/qcom/camss/camss-vfe.c @@ -828,7 +828,7 @@ static int vfe_disable_output(struct vfe_line *line) output->gen2.active_num = 0; spin_unlock_irqrestore(&vfe->output_lock, flags); - return vfe_reset(vfe); + return 0; } /* @@ -850,7 +850,8 @@ int vfe_disable(struct vfe_line *line) mutex_lock(&vfe->stream_lock); - vfe->stream_count--; + if (--vfe->stream_count == 0) + ret = vfe_reset(vfe); mutex_unlock(&vfe->stream_lock); --- bod