From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 CC2C57262A; Mon, 14 Jul 2025 16:30:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752510636; cv=none; b=EY/cPgJ3KjUS86hq1eqxIf5swPt0XVpL1PWTosjDwVWQQ3F25Gy5/sWll3KaMFCTGyV0f4AINwvsmherIAyFE/rAsOWG0w7Z4Az1ZTkhLHZocVOwfkzD6Kml1Ilu/OzeG5Uq9kzz6OWkoCUe3QMU7+hGQnYhHcw99mPsPdpwo4Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752510636; c=relaxed/simple; bh=lpG4IZ6Ioq/EzhqQaI7oezuh5rcGhQxbRRwnUfAZ4QU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=k/0GrvvP7tF4q8u2naAoTVIR85CsfWLoZHVdyOZh//LTMfv2Mdq2hLyXYu3RTmkWauQKiSaKej3rLIS4gBY87izOYOlV6vtNt4e5lSBrq5dqxMCm4NLTKww4Rd4K/ZxnLbJkds/2QLWlFG7kTYfLI2JKTylsALeIcGH3D1r5SpU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=UqK26IC3; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="UqK26IC3" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id C7AC11127; Mon, 14 Jul 2025 18:30:00 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1752510601; bh=lpG4IZ6Ioq/EzhqQaI7oezuh5rcGhQxbRRwnUfAZ4QU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UqK26IC3nrteCaDdSqP4/6c5LRJvIFIKHrPP5hoaIEntyWXbglU0Ud7wrmyYOE09Q b52LWzlDeplUKoLkikXQ7jdTUw2wUxSueHsUV8heHEKyg0qqzuOpkW5m5S3yZnR3vs htRQ7bNTqyiHfISZ57ALngPRq/z9fJTNvQSmqMFs= Date: Mon, 14 Jul 2025 19:30:01 +0300 From: Laurent Pinchart To: Ricardo Ribalda Cc: Hans Verkuil , Hans de Goede , Mauro Carvalho Chehab , Sakari Ailus , Greg Kroah-Hartman , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Linus Walleij , Bartosz Golaszewski , "Rafael J. Wysocki" , Len Brown , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH v2 12/12] media: uvcvideo: Do not create MC entities for virtual entities Message-ID: <20250714163001.GB20231@pendragon.ideasonboard.com> References: <20250605-uvc-orientation-v2-0-5710f9d030aa@chromium.org> <20250605-uvc-orientation-v2-12-5710f9d030aa@chromium.org> <20250629180534.GN24912@pendragon.ideasonboard.com> <20250714143617.GK8243@pendragon.ideasonboard.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Mon, Jul 14, 2025 at 06:04:50PM +0200, Ricardo Ribalda wrote: > On Mon, 14 Jul 2025 at 16:36, Laurent Pinchart wrote: > > On Tue, Jul 08, 2025 at 08:28:21AM +0200, Ricardo Ribalda wrote: > > > On Tue, 1 Jul 2025 at 13:20, Ricardo Ribalda wrote: > > > > On Sun, 29 Jun 2025 at 20:06, Laurent Pinchart wrote: > > > > > Hi Ricardo, > > > > > > > > > > Thank you for the patch. > > > > > > > > > > I would use "software entities" and not "virtual entities" in the > > > > > subject line and everywhere else, as those entities are not virtual. > > > > > > > > > > On Thu, Jun 05, 2025 at 05:53:05PM +0000, Ricardo Ribalda wrote: > > > > > > Neither the GPIO nor the SWENTITY entities form part of the device > > > > > > pipeline. We just create them to hold emulated uvc controls. > > > > > > > > > > > > When the device initializes, a warning is thrown by the v4l2 core: > > > > > > uvcvideo 1-1:1.0: Entity type for entity SWENTITY was not initialized! > > > > > > > > > > > > There are no entity function that matches what we are doing here, and > > > > > > it does not make to much sense to create a function for entities that > > > > > > do not really exist. > > > > > > > > > > I don't agree with this. The purpose of reporting entities to userspace > > > > > through the MC API is to let application enumerate what entities a > > > > > device contains. Being able to enumerate software entities seems as > > > > > useful as being able to enumerate hardware entities. > > > > > > > > What function shall we use in this case? Nothing here seems to match a > > > > software entity > > > > https://www.kernel.org/doc/html/latest/userspace-api/media/mediactl/media-types.html > > > > > > > > Any suggestion for name? > > > > Shall we just live with the warning in dmesg? > > > > > > I just realised that if/when we move to the control framework, the > > > software entity will be gone.... So to avoid introducing a uAPI change > > > that will be reverted later I think that we should keep this patch. > > > > You know my opinion about moving to the control framework, so that's not > > a very compelling argument :-) > > Correct me if I am wrong, your opinion is that it will take too much > work, not that it can't be done or that it is a bad idea. My opinion is that it's not worth the time needed to write patches, nor the time needed to review them. It would be a big change, with risks of regressions, for minimal gain, if any. I don't know if it can be done, but I think it's a bad idea. Don't fix something that isn't broken, the patches backlog is big enough, let's focus on useful changes. > Will send a patch using MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER, but > when/if we use the control framework, please let me drop the swentity. > > Thanks! > > > We could use MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER, as that's the > > function already used by XUs, and the SWENTITY fulfills the same role as > > XUs in some devices. > > > > > > > > Do not create MC entities for them and pretend nothing happened here. > > > > > > > > > > > > Signed-off-by: Ricardo Ribalda > > > > > > --- > > > > > > drivers/media/usb/uvc/uvc_entity.c | 10 ++++++++++ > > > > > > 1 file changed, 10 insertions(+) > > > > > > > > > > > > diff --git a/drivers/media/usb/uvc/uvc_entity.c b/drivers/media/usb/uvc/uvc_entity.c > > > > > > index d1a652ef35ec34801bd39a5124b834edf838a79e..2dbeb4ab0c4c8cc763ff2dcd2d836a50f3c6a040 100644 > > > > > > --- a/drivers/media/usb/uvc/uvc_entity.c > > > > > > +++ b/drivers/media/usb/uvc/uvc_entity.c > > > > > > @@ -72,6 +72,16 @@ static int uvc_mc_init_entity(struct uvc_video_chain *chain, > > > > > > { > > > > > > int ret; > > > > > > > > > > > > + /* > > > > > > + * Do not initialize virtual entities, they do not really exist > > > > > > + * and are not connected to any other entities. > > > > > > + */ > > > > > > + switch (UVC_ENTITY_TYPE(entity)) { > > > > > > + case UVC_EXT_GPIO_UNIT: > > > > > > + case UVC_SWENTITY_UNIT: > > > > > > + return 0; > > > > > > + } > > > > > > + > > > > > > if (UVC_ENTITY_TYPE(entity) != UVC_TT_STREAMING) { > > > > > > u32 function; > > > > > > -- Regards, Laurent Pinchart