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 alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (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 857F5C77B75 for ; Fri, 21 Apr 2023 09:13:26 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 6F1D4E74; Fri, 21 Apr 2023 11:12:33 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 6F1D4E74 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1682068403; bh=Qwt1TCpcI1FTF1sSeARR+lskNtBbhAjtBeQpWoeyD/I=; h=Date:From:To:Subject:References:In-Reply-To:CC:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=ch19hb7ueDPvGngH7mOeSe6l3bYufmwpKiVH34/Emr1xNVR6ZnqkG1F7r4WjW93D3 CnWhS9IBZIBERCZw1XD8aCYnrX4Sii/E+Qk8dxvrMTzQPCfbCQzahwiSFKwdGF9G7u gL92YZPgbGwZnkpZ6OE86cjYMxdZAhJjX/ao7i54= Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 9C7DAF80155; Fri, 21 Apr 2023 11:12:07 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 4F1BFF80155; Fri, 21 Apr 2023 11:12:02 +0200 (CEST) Received: from bluemchen.kde.org (bluemchen.kde.org [IPv6:2001:470:142:8::100]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 02245F800F8 for ; Fri, 21 Apr 2023 11:11:57 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 02245F800F8 Received: from ugly.fritz.box (localhost [127.0.0.1]) by bluemchen.kde.org (Postfix) with ESMTP id A1222241D0; Fri, 21 Apr 2023 05:11:55 -0400 (EDT) Received: by ugly.fritz.box (masqmail 0.3.4, from userid 1000) id 1ppmo7-w8T-00; Fri, 21 Apr 2023 11:11:55 +0200 Date: Fri, 21 Apr 2023 11:11:55 +0200 From: Oswald Buddenhagen To: Takashi Iwai Subject: Re: [RFC PATCH] docs: sound: kernel-api: writing-an-alsa-driver.rst: add FIXMEs Message-ID: Mail-Followup-To: Takashi Iwai , alsa-devel@alsa-project.org, Jaroslav Kysela References: <20230405201220.2197878-1-oswald.buddenhagen@gmx.de> <87sfddv7e4.wl-tiwai@suse.de> <87wn26u32c.wl-tiwai@suse.de> <87leimtyqw.wl-tiwai@suse.de> <87leilsjgk.wl-tiwai@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <87leilsjgk.wl-tiwai@suse.de> Message-ID-Hash: ONUDN5SQVUKIGBBDGIZMFOTFIMKXD6AH X-Message-ID-Hash: ONUDN5SQVUKIGBBDGIZMFOTFIMKXD6AH X-MailFrom: ossi@kde.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: alsa-devel@alsa-project.org X-Mailman-Version: 3.3.8 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Fri, Apr 21, 2023 at 10:55:23AM +0200, Takashi Iwai wrote: >> i suppose we'd have to add SNDRV_CTL_ELEM_ACCESS_{PLAYBACK,CAPTURE}. >> both could be set for unspecific and actually bidirectional >> controls. if neither is set, user space would fall back to the keyword >> based rules (and exceptions ...) - that would be backwards compatible >> and would enable a gradual migration. > >The backward compatibility isn't really easy as you wrote, I'm >afraid. If you run an old user-space stuff on the new kernel, you >must not fill that new information bit but translate it to the string >suffix instead; and that has to be done inside the kernel >automagically. > right, i didn't mention it, but i imagined the strings to remain the same, both for backwards compat, and because they serve a "label" function regardless of semantic interpretation. of course that would make them partially redundant with the newly added bits, but that doesn't seem too bad to me. anyway, i think i have enough background info now to write a nice paragraph for the docu. thanks!