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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 2DE6DC433E0 for ; Thu, 6 Aug 2020 12:29:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E83F22DFB for ; Thu, 6 Aug 2020 12:29:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596716987; bh=15Y36StYY4iLXnVd4QQeJi/iwqwtVIubaSLXu/Ed4wM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=VFgnIerLpSBYsn4D/aFGRornWdJzfNtKa4/hfLK35/HVOOoWBZsUYy3zQD53KEt5e eZz9xonEGMAIU14r2KWx2yelcSulIKSFRswx6E6ZkKydCK5g23GRTsXxqs0ZDI0KLy jq89EwWKLQ+0Xg1TUmHFyDAAQHERL0IUtUPK3Lpw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728919AbgHFMYo (ORCPT ); Thu, 6 Aug 2020 08:24:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:54650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727081AbgHFLPg (ORCPT ); Thu, 6 Aug 2020 07:15:36 -0400 Received: from localhost (unknown [122.171.202.192]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5111A204FD; Thu, 6 Aug 2020 11:08:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596712097; bh=15Y36StYY4iLXnVd4QQeJi/iwqwtVIubaSLXu/Ed4wM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LBkShuRw6J2te4O6AWDiRukKL6OXnClqE3VYlOty5A/1jwasG88skIcK9vcLcxNo4 EKhghtFudkl9hziFOQReHfutbJ6HULIXRcj+IJs8Estw4LurSyWAElN1TD+1r6bDw+ lDDVlhgQmXQPaeiBnJKQu9I/YKO05WwiH6sIIC5o= Date: Thu, 6 Aug 2020 16:38:13 +0530 From: Vinod Koul To: Takashi Iwai Cc: Srinivas Kandagatla , broonie@kernel.org, perex@perex.cz, tiwai@suse.com, lgirdwood@gmail.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, ckeepax@opensource.cirrus.com Subject: Re: [RFC PATCH v2 0/6] ALSA: compress: add support to change codec profile in gapless playback Message-ID: <20200806043010.GC12965@vkoul-mobl> References: <20200721170007.4554-1-srinivas.kandagatla@linaro.org> <20200723130522.GB12965@vkoul-mobl> <20200723155612.GC12965@vkoul-mobl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23-07-20, 22:33, Takashi Iwai wrote: > On Thu, 23 Jul 2020 17:56:12 +0200, > Vinod Koul wrote: > > > > On 23-07-20, 15:17, Takashi Iwai wrote: > > > On Thu, 23 Jul 2020 15:05:22 +0200, > > > Vinod Koul wrote: > > > > > > > > On 23-07-20, 14:38, Takashi Iwai wrote: > > > > > On Tue, 21 Jul 2020 19:00:01 +0200, > > > > > Srinivas Kandagatla wrote: > > > > > > > > > > > > For gapless playback it is possible that each track can have different > > > > > > codec profile with same decoder, for example we have WMA album, > > > > > > we may have different tracks as WMA v9, WMA v10 and so on > > > > > > Or if DSP's like QDSP have abililty to switch decoders on single stream > > > > > > for each track, then this call could be used to set new codec parameters. > > > > > > > > > > > > Existing code does not allow to change this profile while doing gapless > > > > > > playback. > > > > > > > > > > > > This patchset adds new SNDRV_COMPRESS_SET_CODEC_PARAMS IOCTL along with > > > > > > flags in capablity structure to allow userspace to set this new > > > > > > parameters required which switching codec profile, either for gapless > > > > > > or cross fade usecase. > > > > > > > > > > One idea that came up at the previous audio conference regarding this > > > > > implementation was to just allow SET_PARAMS during the stream is > > > > > running (only if the driver sets the capability) instead of > > > > > introducing yet a new ioctl and an ops. > > > > > Would it make sense? > > > > > > > > That does sound good but only issue would be that we need to somehow > > > > mark/document that buffer info is useless and would be discarded, how do > > > > we do that? > > > > > > Yes, the buffer and no_wake_mode can be ignored in the gapless > > > re-setup. Is your concern only about the documentation? Or something > > > else needs to be changed significantly? It's a new scheme in anyway, > > > so the documentation update is required... > > > > My concern is potential abuse of API down the road, if you feel it is > > okay, I am okay with the proposal > > If this can be potentially dangerous, it shouldn't be used, of course. > What kind of scenario could it be? I can think of users trying to invoke this incorrectly, right now we would reject this. Maybe, we can add checks like, if next_track is set and then copy the codec params only to prevent any misuse. Do you think that would be okay? -- ~Vinod 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=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2E9E3C433E0 for ; Thu, 6 Aug 2020 11:09:17 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E334822CA1 for ; Thu, 6 Aug 2020 11:09:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="oAzNq1d5"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="LBkShuRw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E334822CA1 Authentication-Results: mail.kernel.org; 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Thu, 6 Aug 2020 13:08:24 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 05707F80159; Thu, 6 Aug 2020 13:08:23 +0200 (CEST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 886DEF80086 for ; Thu, 6 Aug 2020 13:08:20 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 886DEF80086 Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="LBkShuRw" Received: from localhost (unknown [122.171.202.192]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5111A204FD; Thu, 6 Aug 2020 11:08:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596712097; bh=15Y36StYY4iLXnVd4QQeJi/iwqwtVIubaSLXu/Ed4wM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LBkShuRw6J2te4O6AWDiRukKL6OXnClqE3VYlOty5A/1jwasG88skIcK9vcLcxNo4 EKhghtFudkl9hziFOQReHfutbJ6HULIXRcj+IJs8Estw4LurSyWAElN1TD+1r6bDw+ lDDVlhgQmXQPaeiBnJKQu9I/YKO05WwiH6sIIC5o= Date: Thu, 6 Aug 2020 16:38:13 +0530 From: Vinod Koul To: Takashi Iwai Subject: Re: [RFC PATCH v2 0/6] ALSA: compress: add support to change codec profile in gapless playback Message-ID: <20200806043010.GC12965@vkoul-mobl> References: <20200721170007.4554-1-srinivas.kandagatla@linaro.org> <20200723130522.GB12965@vkoul-mobl> <20200723155612.GC12965@vkoul-mobl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Cc: alsa-devel@alsa-project.org, ckeepax@opensource.cirrus.com, linux-kernel@vger.kernel.org, lgirdwood@gmail.com, tiwai@suse.com, broonie@kernel.org, Srinivas Kandagatla X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On 23-07-20, 22:33, Takashi Iwai wrote: > On Thu, 23 Jul 2020 17:56:12 +0200, > Vinod Koul wrote: > > > > On 23-07-20, 15:17, Takashi Iwai wrote: > > > On Thu, 23 Jul 2020 15:05:22 +0200, > > > Vinod Koul wrote: > > > > > > > > On 23-07-20, 14:38, Takashi Iwai wrote: > > > > > On Tue, 21 Jul 2020 19:00:01 +0200, > > > > > Srinivas Kandagatla wrote: > > > > > > > > > > > > For gapless playback it is possible that each track can have different > > > > > > codec profile with same decoder, for example we have WMA album, > > > > > > we may have different tracks as WMA v9, WMA v10 and so on > > > > > > Or if DSP's like QDSP have abililty to switch decoders on single stream > > > > > > for each track, then this call could be used to set new codec parameters. > > > > > > > > > > > > Existing code does not allow to change this profile while doing gapless > > > > > > playback. > > > > > > > > > > > > This patchset adds new SNDRV_COMPRESS_SET_CODEC_PARAMS IOCTL along with > > > > > > flags in capablity structure to allow userspace to set this new > > > > > > parameters required which switching codec profile, either for gapless > > > > > > or cross fade usecase. > > > > > > > > > > One idea that came up at the previous audio conference regarding this > > > > > implementation was to just allow SET_PARAMS during the stream is > > > > > running (only if the driver sets the capability) instead of > > > > > introducing yet a new ioctl and an ops. > > > > > Would it make sense? > > > > > > > > That does sound good but only issue would be that we need to somehow > > > > mark/document that buffer info is useless and would be discarded, how do > > > > we do that? > > > > > > Yes, the buffer and no_wake_mode can be ignored in the gapless > > > re-setup. Is your concern only about the documentation? Or something > > > else needs to be changed significantly? It's a new scheme in anyway, > > > so the documentation update is required... > > > > My concern is potential abuse of API down the road, if you feel it is > > okay, I am okay with the proposal > > If this can be potentially dangerous, it shouldn't be used, of course. > What kind of scenario could it be? I can think of users trying to invoke this incorrectly, right now we would reject this. Maybe, we can add checks like, if next_track is set and then copy the codec params only to prevent any misuse. Do you think that would be okay? -- ~Vinod