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 C94E412B169 for ; Thu, 31 Oct 2024 10:11:49 +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=1730369512; cv=none; b=Kl2gxggTfdUUaRrsIZjDTWgdcg9mnnb0iXa0f7ZMO9lqfhiFnkDc6I8pPk8AHHghuD/wlG1Ym/uYz6fY8HA/RSjlnHNGj1J9PQ8pDCB4KGQe17cGZY+FLUpxMfPiWRK3ta4mQhWrfInWuA0TUlWdV/3H9GyZPxp9oInenxUAw2E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730369512; c=relaxed/simple; bh=/WOZrhok5cgDteoGhnYKPHeFe4fSDcQR32M0PdOIIfU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=POUAsV5i3Yz/mqHUvA7tbv+LRSbY8Wc8aAa8vh94Jg6F5NJsNhzvKfr39jmvwqdmjldhduyJzRkGnEu0rqcHYug4ouDV7vt8YTQlumglhrr26SOBM3s7X11IclHGsbl5qBIj+kzslclkgbdWHqu7K4++jHFZkyxW46d0qk2pBZ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=Zf7DWRfL; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="Zf7DWRfL" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 877F89EC; Thu, 31 Oct 2024 11:11:44 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1730369504; bh=/WOZrhok5cgDteoGhnYKPHeFe4fSDcQR32M0PdOIIfU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Zf7DWRfL0CKToswod81hWBHr9N+Hb9gf3iGXJGEPCo/KmBRTC6b4UbNeqh8/Tqcgz 1C6GmGg0UymjntTq8N0xYgpORDchwikL6MY2zearA4Lnff7kWyGJROOPF9PT3BVcKQ TXaVYNyMtW7DxrrKB7DaYKNoFN/HXm8wVwg7c/II= Date: Thu, 31 Oct 2024 12:11:41 +0200 From: Laurent Pinchart To: Hans Verkuil Cc: Linux Media Mailing List , Nicolas Dufresne Subject: Re: [PATCH] Documentation: media: improve V4L2_CID_MIN_BUFFERS_FOR_*, doc Message-ID: <20241031101141.GD2473@pendragon.ideasonboard.com> References: <93d078e5-deba-4060-a32e-94bce677453c@xs4all.nl> Precedence: bulk X-Mailing-List: linux-media@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: <93d078e5-deba-4060-a32e-94bce677453c@xs4all.nl> Hi Hans, Thank you for the patch. On Thu, Oct 31, 2024 at 08:50:04AM +0100, Hans Verkuil wrote: > Clearly state that the V4L2_CID_MIN_BUFFERS_FOR_OUTPUT and > V4L2_CID_MIN_BUFFERS_FOR_CAPTURE controls are required for > stateful codecs. Wouldn't it be better for this kind of information to be centralized in a stateful decoder document ? That would make it easier for developers to see all they need to implement. Otherwise they would need to read through the whole documentation to pick the parts of the API they need to support in their drivers. > Signed-off-by: Hans Verkuil > --- > Documentation/userspace-api/media/v4l/control.rst | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/Documentation/userspace-api/media/v4l/control.rst b/Documentation/userspace-api/media/v4l/control.rst > index 57893814a1e5..9253cc946f02 100644 > --- a/Documentation/userspace-api/media/v4l/control.rst > +++ b/Documentation/userspace-api/media/v4l/control.rst > @@ -290,13 +290,15 @@ Control IDs > This is a read-only control that can be read by the application and > used as a hint to determine the number of CAPTURE buffers to pass to > REQBUFS. The value is the minimum number of CAPTURE buffers that is > - necessary for hardware to work. > + necessary for hardware to work. This control is required for stateful > + decoders. > > ``V4L2_CID_MIN_BUFFERS_FOR_OUTPUT`` ``(integer)`` > This is a read-only control that can be read by the application and > used as a hint to determine the number of OUTPUT buffers to pass to > REQBUFS. The value is the minimum number of OUTPUT buffers that is > - necessary for hardware to work. > + necessary for hardware to work. This control is required for stateful > + encoders. > > .. _v4l2-alpha-component: > -- Regards, Laurent Pinchart