From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) (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 10CC219BA5 for ; Tue, 28 Nov 2023 09:31:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="ORlw/Byz" Received: from [100.122.216.38] (ec2-34-240-57-77.eu-west-1.compute.amazonaws.com [34.240.57.77]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: benjamin.gaignard) by madras.collabora.co.uk (Postfix) with ESMTPSA id 8B82466072A7; Tue, 28 Nov 2023 09:31:48 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1701163909; bh=Vutn2VpNZlFhIZAIALs4SpWX2QnshhnRzKmxSnOI2H0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ORlw/Byzy5htbGR8Y31+/LHXfQjuKd+rwevbFT+JIksX2W7F2PzcsW8i5DTQf4ffE NqbM1CuHKQCnqzXpdj8HSP59G0Z0G3kwstxdLxwCOTuO1Vyo2iZI7erSl8ECeC5zCg BKUN0XkN9SEF6JGdQvHv3rOfS2FDIZ+GnkOZ9nVjjCbA89mQBN3OpqRO7D3RJmi4IS sX6d9AErK9gJrerOoMdXRI9MSVrh9SsKVb/vQ45c78Yv/ZgNpnszW/05MpOlNn0CbX i2giUU6FYcCro7D0xjprW9B1+p+2YXZ7ubcsd/yGOXvQiCeUmCdmL7ppmPX7y6/w5j knPR6WOZlwatA== Message-ID: <6fa1ec09-3e30-475e-9718-29d23586753e@collabora.com> Date: Tue, 28 Nov 2023 10:31:45 +0100 Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 07/55] media: imx8-isi: Stop abusing of min_buffers_needed field Content-Language: en-US To: Laurent Pinchart Cc: hverkuil@xs4all.nl, mchehab@kernel.org, tfiga@chromium.org, m.szyprowski@samsung.com, matt.ranostay@konsulko.com, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-staging@lists.linux.dev, kernel@collabora.com, Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team References: <20231127165454.166373-1-benjamin.gaignard@collabora.com> <20231127165454.166373-8-benjamin.gaignard@collabora.com> <20231127170700.GC31314@pendragon.ideasonboard.com> From: Benjamin Gaignard In-Reply-To: <20231127170700.GC31314@pendragon.ideasonboard.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Le 27/11/2023 à 18:07, Laurent Pinchart a écrit : > Hi Benjamin, > > Thank you for the patch. > > On Mon, Nov 27, 2023 at 05:54:06PM +0100, Benjamin Gaignard wrote: >> 'min_buffers_needed' is suppose to be used to indicate the number >> of buffers needed by DMA engine to start streaming. >> imx8-isi driver doesn't use DMA engine and just want to specify > What do you mean, "doesn't use DMA engine" ? The ISI surely has DMA > engines :-) I have done assumption on drivers given if they use or dma_* functions. I have considers that all PCI drivers are using DMA engine and I don't know the design for each drivers so I hope to get this information from maintainers and fix that in v2. If imx8-isi driver needs a minimum number of buffers before start streaming I will do a v2 and use min_dma_buffers_needed instead. Regards, Benjamin > >> the minimum number of buffers to allocate when calling VIDIOC_REQBUFS. >> That 'min_reqbufs_allocation' field purpose so use it. >> >> Signed-off-by: Benjamin Gaignard >> CC: Laurent Pinchart >> CC: Mauro Carvalho Chehab >> CC: Shawn Guo >> CC: Sascha Hauer >> CC: Pengutronix Kernel Team >> CC: Fabio Estevam >> CC: NXP Linux Team >> --- >> drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c >> index 49bca2b01cc6..81673ff9084b 100644 >> --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c >> +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c >> @@ -1453,7 +1453,7 @@ int mxc_isi_video_register(struct mxc_isi_pipe *pipe, >> q->mem_ops = &vb2_dma_contig_memops; >> q->buf_struct_size = sizeof(struct mxc_isi_buffer); >> q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC; >> - q->min_buffers_needed = 2; >> + q->min_reqbufs_allocation = 2; >> q->lock = &video->lock; >> q->dev = pipe->isi->dev; >>