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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95073C0032E for ; Wed, 25 Oct 2023 11:03:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232846AbjJYLDs (ORCPT ); Wed, 25 Oct 2023 07:03:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232695AbjJYLDr (ORCPT ); Wed, 25 Oct 2023 07:03:47 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D011AC for ; Wed, 25 Oct 2023 04:03:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698231825; x=1729767825; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=Z+Tqa05I/dfoZsvdqI9YBnXLxOn84FvXYP9u6xZPNFE=; b=KdkP9GWHu+53/LxKZetnyJAq4D7Eybp1QiVPbLRDe6B67oOugbplaptX nc4Cv6b6/j7YXMar00/J+D8FeX3+oIEjFqnXCc9SSlcfNnphXOUw+rN/e JpNHtYI3VtWRU01vwo79pfeTNVmnA6LDecMaEv57i5P7ucO1PDtrwNua0 UhPpGJ265CIzmkmSydIAkMkIVuTVbmdhjek/N7bD6h5Sp1xHTs7wIi2Od LwwtoVFe9zW1WYCdPaxl+t/Q9fCvtwS1QxXGHln0nmpQu9OPZNFDBYFJZ VhpYP9euwbZzqCJXeilVl4PcD1MOLYbgZOmdX9cSNo4jpzxx7kOv+lgT6 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10873"; a="451509375" X-IronPort-AV: E=Sophos;i="6.03,250,1694761200"; d="scan'208";a="451509375" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Oct 2023 04:03:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10873"; a="882416604" X-IronPort-AV: E=Sophos;i="6.03,250,1694761200"; d="scan'208";a="882416604" Received: from turnipsi.fi.intel.com (HELO kekkonen.fi.intel.com) ([10.237.72.44]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Oct 2023 04:03:42 -0700 Received: from kekkonen.localdomain (localhost [127.0.0.1]) by kekkonen.fi.intel.com (Postfix) with SMTP id 35C8211F82E; Wed, 25 Oct 2023 14:03:39 +0300 (EEST) Date: Wed, 25 Oct 2023 11:03:39 +0000 From: Sakari Ailus To: Laurent Pinchart Cc: Hans Verkuil , linux-media@vger.kernel.org, tomi.valkeinen@ideasonboard.com, jacopo.mondi@ideasonboard.com, bingbu.cao@intel.com, hongju.wang@intel.com Subject: Re: [PATCH v3 5/8] media: v4l: subdev: Make stream argument optional in state access functions Message-ID: References: <20231023174408.803874-1-sakari.ailus@linux.intel.com> <20231023174408.803874-6-sakari.ailus@linux.intel.com> <95c4ed4d-36e5-44f7-8609-dfdb7847b0e8@xs4all.nl> <20231025105055.GC481@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231025105055.GC481@pendragon.ideasonboard.com> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Laurent, On Wed, Oct 25, 2023 at 01:50:55PM +0300, Laurent Pinchart wrote: > Hi Sakari, > > On Wed, Oct 25, 2023 at 10:19:15AM +0000, Sakari Ailus wrote: > > On Wed, Oct 25, 2023 at 11:53:35AM +0200, Hans Verkuil wrote: > > > On 23/10/2023 19:44, Sakari Ailus wrote: > > > > The sub-device state access functions take three arguments: sub-device > > > > state, pad and stream. The stream is not relevant for the majority of > > > > drivers and having to specify 0 for the stream is considered a nuisance. > > > > > > > > Provide a two-argument macros for these state access functions to cover > > > > the needs of stream-unaware users. > > > > > > > > Signed-off-by: Sakari Ailus > > > > --- > > > > drivers/media/v4l2-core/v4l2-subdev.c | 18 ++++++------- > > > > include/media/v4l2-subdev.h | 39 ++++++++++++++++++++------- > > > > 2 files changed, 39 insertions(+), 18 deletions(-) > > > > > > > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c > > > > index f0f0af48730f..e35226587244 100644 > > > > --- a/drivers/media/v4l2-core/v4l2-subdev.c > > > > +++ b/drivers/media/v4l2-core/v4l2-subdev.c > > > > @@ -1671,8 +1671,8 @@ int v4l2_subdev_set_routing_with_fmt(struct v4l2_subdev *sd, > > > > EXPORT_SYMBOL_GPL(v4l2_subdev_set_routing_with_fmt); > > > > > > > > struct v4l2_mbus_framefmt * > > > > -v4l2_subdev_state_get_format(struct v4l2_subdev_state *state, unsigned int pad, > > > > - u32 stream) > > > > +__v4l2_subdev_state_get_format(struct v4l2_subdev_state *state, > > > > + unsigned int pad, u32 stream) > > > > { > > > > struct v4l2_subdev_stream_configs *stream_configs; > > > > unsigned int i; > > > > @@ -1702,11 +1702,11 @@ v4l2_subdev_state_get_format(struct v4l2_subdev_state *state, unsigned int pad, > > > > > > > > return NULL; > > > > } > > > > -EXPORT_SYMBOL_GPL(v4l2_subdev_state_get_format); > > > > +EXPORT_SYMBOL_GPL(__v4l2_subdev_state_get_format); > > > > > > > > struct v4l2_rect * > > > > -v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad, > > > > - u32 stream) > > > > +__v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad, > > > > + u32 stream) > > > > { > > > > struct v4l2_subdev_stream_configs *stream_configs; > > > > unsigned int i; > > > > @@ -1736,11 +1736,11 @@ v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad, > > > > > > > > return NULL; > > > > } > > > > -EXPORT_SYMBOL_GPL(v4l2_subdev_state_get_crop); > > > > +EXPORT_SYMBOL_GPL(__v4l2_subdev_state_get_crop); > > > > > > > > struct v4l2_rect * > > > > -v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state, unsigned int pad, > > > > - u32 stream) > > > > +__v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state, > > > > + unsigned int pad, u32 stream) > > > > { > > > > struct v4l2_subdev_stream_configs *stream_configs; > > > > unsigned int i; > > > > @@ -1770,7 +1770,7 @@ v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state, unsigned int pad, > > > > > > > > return NULL; > > > > } > > > > -EXPORT_SYMBOL_GPL(v4l2_subdev_state_get_compose); > > > > +EXPORT_SYMBOL_GPL(__v4l2_subdev_state_get_compose); > > > > > > > > int v4l2_subdev_routing_find_opposite_end(const struct v4l2_subdev_krouting *routing, > > > > u32 pad, u32 stream, u32 *other_pad, > > > > diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h > > > > index 71cb35133b4a..12eb0fe746d7 100644 > > > > --- a/include/media/v4l2-subdev.h > > > > +++ b/include/media/v4l2-subdev.h > > > > @@ -1545,7 +1545,7 @@ int v4l2_subdev_set_routing_with_fmt(struct v4l2_subdev *sd, > > > > * v4l2_subdev_state_get_format() - Get pointer to a stream format > > > > * @state: subdevice state > > > > * @pad: pad id > > > > - * @stream: stream id > > > > + * @...: stream id (optional argument) > > > > * > > > > * This returns a pointer to &struct v4l2_mbus_framefmt for the given pad + > > > > * stream in the subdev state. > > > > @@ -1553,15 +1553,22 @@ int v4l2_subdev_set_routing_with_fmt(struct v4l2_subdev *sd, > > > > * For stream-unaware drivers the format for the corresponding pad is returned. > > > > * If the pad does not exist, NULL is returned. > > > > */ > > > > +#define v4l2_subdev_state_get_format(state, pad, ...) \ > > > > + __v4l2_subdev_state_get_format_ ## __VA_OPT__(stream) \ > > > > + (state, pad __VA_OPT__(,) __VA_ARGS__) > > > > +#define __v4l2_subdev_state_get_format_(state, pad) \ > > > > + __v4l2_subdev_state_get_format(state, pad, 0) > > > > +#define __v4l2_subdev_state_get_format_stream(state, pad, stream) \ > > > > + __v4l2_subdev_state_get_format(state, pad, stream) > > > > > > Hmm, 'git grep __VA_OPT__' finds no use of this in the kernel. Are you sure this > > > is safe to use? Does clang support it? Do all gcc versions that the kernel support > > > implement it? > > > > > > A 10+ for creativity, but I'm a bit concerned about it. > > > > :-) > > > > I noticed the problem, too, as the lkp bot failed compiling this on GCC > > 7.5. Indeed only GCC 8 supports __VA_OPT__ but the oldest GCC version > > supported for kernel compilation is 7.1. So __VA_OPT__ isn't... an option. > > > > I thought this could be done using variable arguments, making most error > > handling take place at runtime (for GCC versions not supporting > > __VA_OPT__), but then Laurent figured this can be done with just > > __VA_ARGS__ which is part of C99. > > > > The code would look like this, which is only slightly less understandable > > than with __VA_OPT__: > > > > #define v4l2_subdev_state_get_format(...) \ > > __v4l2_subdev_state_get_format_var(__VA_ARGS__, , _2)(__VA_ARGS__) > > How about > > __v4l2_subdev_state_get_format_var(__VA_ARGS__, _stream, _pad)(__VA_ARGS__) > > ? The internal macro and function names would then be more explicit. Works for me. I'll also rename __v4l2_subdev_state_get_format_var, removing _var. > > > #define __v4l2_subdev_state_get_format_var(_1, _2, _3, NUM, ...) \ > > __v4l2_subdev_state_get_format ## NUM > > #define __v4l2_subdev_state_get_format_2(state, pad) \ > > __v4l2_subdev_state_get_format(state, pad, 0) > > struct v4l2_mbus_framefmt * > > __v4l2_subdev_state_get_format(struct v4l2_subdev_state *state, > > unsigned int pad, u32 stream); > > > > > And if there are only a few drivers that need to give a specific stream, > > > wouldn't it be easier to just have a v4l2_subdev_state_get_format_stream > > > function and a static inline v4l2_subdev_state_get_format() that just calls > > > the _stream version with 0? > > > > I'm trying to shorten function names here: they're overly long. Also I'd > > like to see a single set of API functions to access sub-device state > > information irrespective of how it is stored. I originally proposed just > > specifying stream zero but both Laurent and Tomi opined against it. > -- Regards, Sakari Ailus