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 X-Spam-Level: X-Spam-Status: No, score=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 165EBC433DB for ; Fri, 12 Feb 2021 12:07:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D99CB64E05 for ; Fri, 12 Feb 2021 12:07:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231289AbhBLMHw (ORCPT ); Fri, 12 Feb 2021 07:07:52 -0500 Received: from mx2.suse.de ([195.135.220.15]:54592 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231300AbhBLMHr (ORCPT ); Fri, 12 Feb 2021 07:07:47 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1613131619; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=EowUVygo2zWBdYrKdInlBnVZElDG6W1BRBMq1KZA4PQ=; b=VTNBckwI8AjjwpldT/Cw6nYYZkAJXHBsQuKpKnappgkHfBohpi1dV883BSuClkE1ERXoYd CeOwxX5M1cEtQt4k1RppQq/lbhyfLREHEI3PAaZ+QSGRlcegRvS0uU88MnEzl1thCTgRR/ j6O7xaWR5wVlFGaE8xjuG5Zmw57fFbY= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 95D77AC90; Fri, 12 Feb 2021 12:06:59 +0000 (UTC) Date: Fri, 12 Feb 2021 13:06:59 +0100 From: Petr Mladek To: Sakari Ailus Cc: Andy Shevchenko , Linux Kernel Mailing List , Linux Media Mailing List , Dave Stevenson , dri-devel , Hans Verkuil , Laurent Pinchart , Mauro Carvalho Chehab , Sergey Senozhatsky , Steven Rostedt , Joe Perches , Jani Nikula , Rasmus Villemoes Subject: Re: [PATCH v6 1/3] lib/vsprintf: Add support for printing V4L2 and DRM fourccs Message-ID: References: <20210208200903.28084-1-sakari.ailus@linux.intel.com> <20210208200903.28084-2-sakari.ailus@linux.intel.com> <20210209092032.GC32460@paasikivi.fi.intel.com> <20210209174755.GH32460@paasikivi.fi.intel.com> <20210212112856.GE3@paasikivi.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210212112856.GE3@paasikivi.fi.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Fri 2021-02-12 13:28:56, Sakari Ailus wrote: > On Thu, Feb 11, 2021 at 06:14:28PM +0100, Petr Mladek wrote: > > On Tue 2021-02-09 19:47:55, Sakari Ailus wrote: > > > Hi Andy, > > > > > > On Tue, Feb 09, 2021 at 11:58:40AM +0200, Andy Shevchenko wrote: > > > > On Tue, Feb 09, 2021 at 11:20:32AM +0200, Sakari Ailus wrote: > > > > > On Mon, Feb 08, 2021 at 10:43:30PM +0200, Andy Shevchenko wrote: > > > > > > On Mon, Feb 8, 2021 at 10:11 PM Sakari Ailus > > > > > > wrote: > > > > > > > > > > > + %p4cc BG12 little-endian (0x32314742) > > > > > > > > > > > > This misses examples of the (strange) escaping cases and wiped > > > > > > whitespaces to make sure everybody understands that 'D 12' will be the > > > > > > same as 'D1 2' (side note: which I disagree on, perhaps something > > > > > > should be added into documentation why). > > I discussed this with Hans and we concluded spaces shouldn't be dropped. > > Spaces can be present in the codes themselves in any case. Great! > > > > > > > > > > ... > > > > > > > > > > > +static noinline_for_stack > > > > > > > +char *fourcc_string(char *buf, char *end, const u32 *fourcc, > > > > > > > + struct printf_spec spec, const char *fmt) > > > > > > > +{ > > > > > > > > > > > > > + char output[sizeof("(xx)(xx)(xx)(xx) little-endian (0x01234567)")]; > > > > > > > > > > > > Do we have any evidence / document / standard that the above format is > > > > > > what people would find good? From existing practices (I consider other > > > > > > printings elsewhere and users in this series) I find '(xx)' form for > > > > > > hex numbers is weird. The standard practice is to use \xHH (without > > > > > > parentheses). > > > > > > > > > > Earlier in the review it was proposed that special handling of codes below > > > > > 32 should be added, which I did. Using the parentheses is apparently an > > > > > existing practice elsewhere. > > > > > > > > Where? \xHH is quite well established format for escaping. Never heard about > > > > '(xx)' variant before this very series. > > > > What about using the same approach as drm_get_format_name()? > > I mean printing '?' when the character is not printable. > > The exact value is printed later anyway. > > > > The advantage is that it will always printk 4 characters. > > "?" can be expanded by the shell. We (me and Hans) both though a dot (".") > would be good. These aren't going to be present in valid fourcc codes in > any case. The dot (".") looks fine to me. Best Regards, Petr