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 D44ADC433EF for ; Mon, 30 May 2022 10:14:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235182AbiE3KOi (ORCPT ); Mon, 30 May 2022 06:14:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235157AbiE3KOa (ORCPT ); Mon, 30 May 2022 06:14:30 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9FDD73792 for ; Mon, 30 May 2022 03:14:28 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 775AD1FA1A; Mon, 30 May 2022 10:14:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1653905667; 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=v+FA2ubRvi/QvayaIAXldHKc3DSqQn1Flnho54j7V/c=; b=QNbqLpLaXA2W9HHeRWSvOjYr8HDS4j+CpCjHWHt707OBt1yiqDVzypx2gAjdE8u66cvyJ3 mwF9g1Q0fB+JYTA8DZvr2f5U1kIXrTEfaqXj+juaVpGYCRn2uKQHUxqkO6wQq/yq81hzJx WKs+TOExp8vcbr/8QwDBCLacTKXtuaM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1653905667; 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=v+FA2ubRvi/QvayaIAXldHKc3DSqQn1Flnho54j7V/c=; b=Ijy+1zj7zziK86qBUY6YTrMp1RkiokIsDp1S6oRQZb9agJKlBAVy0UGUEWWUxEdL0fyOwy Q6KSyEaBys1+vlAg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 4CFE913AFD; Mon, 30 May 2022 10:14:27 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id hLPtEQOZlGKBSQAAMHmgww (envelope-from ); Mon, 30 May 2022 10:14:27 +0000 Date: Mon, 30 May 2022 12:14:26 +0200 Message-ID: <87a6azxr7h.wl-tiwai@suse.de> From: Takashi Iwai To: Charles Keepax Cc: Vitaly Rodionov , Jaroslav Kysela , Takashi Iwai , Mark Brown , , , Subject: Re: [PATCH v4 00/17] ALSA: hda: cirrus: Add initial DSP support and firmware loading In-Reply-To: <20220530093639.GT38351@ediswmail.ad.cirrus.com> References: <20220525131638.5512-1-vitalyr@opensource.cirrus.com> <871qwf0x8t.wl-tiwai@suse.de> <20220530090846.GS38351@ediswmail.ad.cirrus.com> <87czfvxtsc.wl-tiwai@suse.de> <20220530093639.GT38351@ediswmail.ad.cirrus.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 30 May 2022 11:36:39 +0200, Charles Keepax wrote: > > On Mon, May 30, 2022 at 11:18:43AM +0200, Takashi Iwai wrote: > > On Mon, 30 May 2022 11:08:46 +0200, > > Charles Keepax wrote: > > > > > > On Fri, May 27, 2022 at 06:13:38PM +0200, Takashi Iwai wrote: > > > > On Wed, 25 May 2022 15:16:21 +0200, > > > > Vitaly Rodionov wrote: > > > > The idea to add / delete controls by the control element change > > > > doesn't sound good; as already mentioned in my reply to the previous > > > > patch set, the change of the control elements can be triggered too > > > > easily by any normal users who have the access to the sound devices. > > > > It means thousands of additions and removals per second could be > > > > attacked by any user. > > > > > > > > > > This I am a little less sure how we handle. I mean arn't there > > > already a few ways to do this? Both the existing ASoC wm_adsp > > > stuff, and the topology stuff (used on all new Intel platforms, > > > so very widely deployed) let you create controls by loading a > > > firmware file. Also within ALSA itself can't user-space create > > > user ALSA controls? Is there some rate limiting on that? How is > > > this issue tackled there? > > > > The creation of kctls via firmware loading would be OK, as the code > > path can't be triggered so frequently. Is it the case for this patch > > set? There was too little information about the implementation (and > > more importantly, how to use the controls), so it's hard to judge... > > > > Yeah that should be what is happening here. Although it looks > like this code might be removing all the controls if the firmware > is unloaded. I will discuss that with the guys, we normal just > disable the controls on the wm_adsp stuff. OK, that sounds good. Basically my concern came up from the code snippet doing asynchronous addition/removal via work. This showed some yellow signal, as such a pattern doesn't appear in the normal implementation. If this is (still) really necessary, it has to be clarified as an exception. thanks, Takashi