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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFE65C433EF for ; Wed, 29 Sep 2021 14:40:47 +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 094B4613CD for ; Wed, 29 Sep 2021 14:40:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 094B4613CD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id BE54B16A1; Wed, 29 Sep 2021 16:39:53 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz BE54B16A1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1632926443; bh=JUv26bWNqvWWShhRrJlrmsT1ljSqcVV+JRiPJvZnmjU=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=pacasH9b3rmz7roTMDcLhares6HtgCwo2NXMdtkEE3o8RGhX3RPB0RbXQsBZlfVXF 8caNZ4mYIe+91mYgxqdkLREHowY7agPNh8VRulXwck+xon2/yn11ctvC707WbL0rXR i14D+grsUVH0J9tXWizJp69ebEPLGGJKXkDeTeWQ= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 46DD1F801F7; Wed, 29 Sep 2021 16:39:53 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id B4720F80227; Wed, 29 Sep 2021 16:39:51 +0200 (CEST) Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 2A2FAF80105 for ; Wed, 29 Sep 2021 16:39:44 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 2A2FAF80105 Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="lz7whm1j"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="qperrNir" Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 6AD1320305; Wed, 29 Sep 2021 14:39:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1632926384; 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=/6iJrWDJhYdAKN7krf7oD+B0/LPQPAqhppG3nSySK0k=; b=lz7whm1jH/r4iLYVXH4mAgfDWoJuX954YB6FCgBEzyKBbnwTwxDvLgHSJqZBewgsudANyb WxkgvfVgUWyYIVGlr3gncu2yG0K+riKZPQVMmy4smY+atzeHGQBu2vlxgDi/IhwLTGLqXG q7d6uc1psLPmvwPj4nfEWnqzUbNOF7w= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1632926384; 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=/6iJrWDJhYdAKN7krf7oD+B0/LPQPAqhppG3nSySK0k=; b=qperrNirGnI5I7FBN1ZhqmJXRnNrhwcmipoj6joSeo+/ORB1fH/7VHfbUbZosKzE39yfQX 1f9md+M/0LXJyIAQ== Received: from alsa1.suse.de (alsa1.suse.de [10.160.4.42]) by relay2.suse.de (Postfix) with ESMTP id 5A674A3B8F; Wed, 29 Sep 2021 14:39:44 +0000 (UTC) Date: Wed, 29 Sep 2021 16:39:44 +0200 Message-ID: From: Takashi Iwai To: Pierre-Louis Bossart Subject: Re: [PATCH v2 1/2] ALSA: hda: Reduce udelay() at SKL+ position reporting In-Reply-To: References: <20210929072934.6809-1-tiwai@suse.de> <20210929072934.6809-2-tiwai@suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Cc: Jens Axboe , alsa-devel@alsa-project.org 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 Wed, 29 Sep 2021 16:15:44 +0200, Pierre-Louis Bossart wrote: > > > > @@ -874,11 +896,7 @@ static unsigned int azx_get_pos_skl(struct azx *chip, struct azx_dev *azx_dev) > > if (azx_dev->core.substream->stream == SNDRV_PCM_STREAM_PLAYBACK) > > return azx_skl_get_dpib_pos(chip, azx_dev); > > > > - /* For capture, we need to read posbuf, but it requires a delay > > - * for the possible boundary overlap; the read of DPIB fetches the > > - * actual posbuf > > - */ > > - udelay(20); > > + /* read of DPIB fetches the actual posbuf */ > > azx_skl_get_dpib_pos(chip, azx_dev); > > I don't think extra read has any effect, it could be removed.... > > > return azx_get_pos_posbuf(chip, azx_dev); > > } > > The suggestion was to further simplify with > > static unsigned int azx_get_pos_skl(struct azx *chip, struct azx_dev > *azx_dev) > { > return azx_get_pos_posbuf(chip, azx_dev); > } > > i.e. same behavior on playback and capture. that's the recommendation > from Intel hw folks. It's achieved in the second patch. Takashi