From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 169EBC021B2 for ; Thu, 20 Feb 2025 14:51:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zW/QroSyw9nssqvzZ/17qcsPywHnncdKaasw/hBPe2Q=; b=Uzrz0AEKgN3686 xpW9xZZW26s/SWXQu+ks+JAQKEJgePT3fW/10+Lsrdy7DIoD7RLjsrEJIKn0OZbyzFSgpU1Hy0Rg5 iq99AicevCLMCjCK/9OMTHOXo98d3Pjy6vQFGRifHH6S2MJhPi+a3PUFWKy/jGcfi+FpvdrJW495P E8FI/Ll8lpec4XnVtjZ1cCv+g54nYOFzdSjcRpBZSY9Afr/rSSubvukzFWG+ngRy73FspBuYh4o+W Tp01RbLL/2yLen2OyGcYRGwGJ2ehN79FEE4hX/V6Gw2U3fJ/d4s8KoCrJ6Srr0QOy+GThjglXQG8m Qjgv6m1X6LkkdMZwVFYA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tl7u1-00000001Phd-1oTx; Thu, 20 Feb 2025 14:51:49 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tl7tP-00000001PZF-3SWx for linux-rockchip@lists.infradead.org; Thu, 20 Feb 2025 14:51:13 +0000 Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id C59061193; Thu, 20 Feb 2025 15:49:46 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1740062987; bh=q9znbXfjIwN4GvMstwCS771yptKk8cRWefooM3wCPSQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sQM+OmaT/EyC0D1KvDm2dLdDCMOIpWwjdIh8qAhx9Mcf3cSLivxSN/3Q+lsv5toxB bUxBODQSJ0E2qP1+/rVIUBdnCcktYgDVBEUeknJK5OY3P1AIb+TATRi3hCdMTGo4uo E+Y8ibq1ggc0WZC22pZj6GCvBuCtBrWBvDI7CZZY= Date: Thu, 20 Feb 2025 16:50:54 +0200 From: Laurent Pinchart To: Jacopo Mondi Cc: Hans Verkuil , Mauro Carvalho Chehab , Sakari Ailus , Dafna Hirschfeld , "open list:ROCKCHIP ISP V1 DRIVER" , Heiko Stuebner , "open list:ROCKCHIP ISP V1 DRIVER" , Adam Pigg Subject: Re: [PATCH v3] media: rkisp1: Remove min_queued_buffers Message-ID: <20250220145054.GA18213@pendragon.ideasonboard.com> References: <20241029082117.55385-1-jacopo.mondi@ideasonboard.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250220_065112_005633_CD09D30D X-CRM114-Status: GOOD ( 37.59 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org Hi Jacopo, On Thu, Feb 20, 2025 at 03:22:44PM +0100, Jacopo Mondi wrote: > On Tue, Oct 29, 2024 at 09:21:16AM +0100, Jacopo Mondi wrote: > > There apparently is no reason to require 3 queued buffers for RkISP1, > > as the driver operates with a scratch buffer where data can be > > directed to if there's no available buffer provided by userspace. > > > > Reduce the number of required buffers to 0 by removing the > > initialization of min_queued_buffers, to allow applications to operate > > by queueing capture buffers on-demand. > > > > Tested with libcamera, by operating with a single capture request. The > > same request (and the associated capture buffer) gets recycled once > > completed. This of course causes a frame rate drop but doesn't hinder > > operations. > > > > Signed-off-by: Jacopo Mondi > > I just noticed v2 of this series: > media: rkisp1: Reduce min_queued_buffers to 1 > > has been collected instead of this v3. That's my fault, I apologize. > And I noticed because a user complained to me about this. > > Now, I can provide an update based on the now merged v2, not a big > deal, but this depresses me a bit as the discussion about > implementing multi-commiter model is apparently (again) stalled. > > I know, sh*t happens (TM) and hiccups are expected in the process, > we all make mistakes and I'm not even sure through which path the > patch has been collected, but I could have handled this one easily, > and instead what we have is: > > 1) an unhappy user that will likely have to wait for the next release > 2) me having to send an additional (rather trivial) patch > 3) Someone will have to review, collect, PR etc etc > > (and I'm not even mentioning this patch is 3 lines) > > Issues like this one seems to be considered a fact of life we decided > is fine to live with, while every possible corner case of the proposed > multi-committer model is analyzed with great concern like we're > trading a perfect model for something that has to be equally perfect. > > And while I agree the biggest reason for the proverbial v4l2 slow pace > is the reviewers scarcity and the limited maintainers bandwidth, now > that we have everything in place to reduce the system clogginess > it still seems we're not all sold for it. I really don't get it, sorry. Amen. > > --- > > v2->v3: > > - Remove min_queued_buffers initialization > > > > v1->v2: > > The first version of this patch set min_queued_buffers to 1, but setting it > > to 0 doesn't compromise operations and it's even better as it allows application > > to queue buffers to the capture devices on-demand. If a buffer is not provided > > to the DMA engines, image data gets directed to the driver's internal scratch > > buffer. > > --- > > drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c | 3 --- > > 1 file changed, 3 deletions(-) > > > > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c > > index 2bddb4fa8a5c..2f0c610e74b9 100644 > > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c > > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c > > @@ -35,8 +35,6 @@ > > #define RKISP1_SP_DEV_NAME RKISP1_DRIVER_NAME "_selfpath" > > #define RKISP1_MP_DEV_NAME RKISP1_DRIVER_NAME "_mainpath" > > > > -#define RKISP1_MIN_BUFFERS_NEEDED 3 > > - > > enum rkisp1_plane { > > RKISP1_PLANE_Y = 0, > > RKISP1_PLANE_CB = 1, > > @@ -1563,7 +1561,6 @@ static int rkisp1_register_capture(struct rkisp1_capture *cap) > > q->ops = &rkisp1_vb2_ops; > > q->mem_ops = &vb2_dma_contig_memops; > > q->buf_struct_size = sizeof(struct rkisp1_buffer); > > - q->min_queued_buffers = RKISP1_MIN_BUFFERS_NEEDED; > > q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC; > > q->lock = &node->vlock; > > q->dev = cap->rkisp1->dev; -- Regards, Laurent Pinchart _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip