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 66F57C433EF for ; Thu, 3 Mar 2022 15:58:07 +0000 (UTC) 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 7F8A01A8E; Thu, 3 Mar 2022 16:57:15 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 7F8A01A8E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1646323085; bh=wVV683G32lWrWOQ/DHwVqiEhQrAcp8Gi7OZjZHylJYU=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=J/sriUORAg4ekkjyXznda7n4mjX8W1ZA8NfQVunURH4tq+12ZYn+kb2oQM9thFz0i 0yESTYZ+5CLL3ANfvflx+EO2jgAMS0jsWeiEsz52iOu+XCT9qWSXRemRwxtb8a6R1N tMDy9Zb1koyfRDRDMeFkwnajc1LkcIJyDHPSlZI0= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 2A3D9F80149; Thu, 3 Mar 2022 16:57:15 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 64A40F80152; Thu, 3 Mar 2022 16:57:13 +0100 (CET) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) (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 2A3D7F80109 for ; Thu, 3 Mar 2022 16:57:10 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 2A3D7F80109 Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="a4s9TCdW"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="EwnAxxjL" Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 2FEAA21997; Thu, 3 Mar 2022 15:57:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1646323030; 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=hvZmFNZwfGxsY3SATvOq/0RvuhCsxHAsW+4kENTqBbo=; b=a4s9TCdW/yzAYO1oRXysgx5dThhmhpxhs7Ghdq3kWQlXNLIzzqR1/BHZERfKfgtPykgv2q lakGqqxxuOpZh7JfRBOE/ctpRimLHIMWm39pC/2zgbcuW6y9GFT+L5qQpPu5hC20lWAooX Ks3S+2xUenUEzWgcfrLpAvcPxSeuM7g= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1646323030; 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=hvZmFNZwfGxsY3SATvOq/0RvuhCsxHAsW+4kENTqBbo=; b=EwnAxxjLRhdeF+cTQoUWPyKdBD7m+sJJID8xKkIK/0maMIruUOM50y8Y6KQbl39wBt+bhq C/HX6idcEGy+J5Cw== Received: from alsa1.suse.de (alsa1.suse.de [10.160.4.42]) by relay2.suse.de (Postfix) with ESMTP id 196BCA3B88; Thu, 3 Mar 2022 15:57:10 +0000 (UTC) Date: Thu, 03 Mar 2022 16:57:10 +0100 Message-ID: From: Takashi Iwai To: Shengjiu Wang Subject: Re: Issue in pcm_dsnoop.c in alsa-lib In-Reply-To: References: 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: alsa-devel@alsa-project.org, chancel.liu@nxp.com, Shengjiu Wang 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 Tue, 01 Mar 2022 05:16:38 +0100, Shengjiu Wang wrote: > > Hi Takashi Iwai, Jaroslav Kysela > > We encountered an issue in the pcm_dsnoop use case, could you please > help to have a look? > > *Issue description:* > With two instances for dsnoop type device running in parallel, after > suspend/resume, one of the instances will be hung in memcpy because the > very large copy size is obtained. > > #3 0x0000ffffa78d5098 in snd_pcm_dsnoop_sync_ptr (pcm=0xaaab06563da0) > at pcm_dsnoop.c:158 > dsnoop = 0xaaab06563c20 > slave_hw_ptr = 64 > old_slave_hw_ptr = 533120 > avail = *187651522444320* > > * Reason analysis: * > The root cause that I analysis is that after suspend/resume, one > instance will get the SND_PCM_STATE_SUSPENDED state from slave pcm device, > then it will do snd_pcm_prepare() and snd_pcm_start(), which will reset > the dsnoop->slave_hw_ptr and the hw_ptr of slave pcm device, then the > state of this instance is correct. But another instance may not get > the SND_PCM_STATE_SUSPENDED state from slave pcm device because slave > device may have been recovered by first instance, so > the dsnoop->slave_hw_ptr is not reset. but because hw_ptr of slave pcm > device has been reset, so there will be a very large "avail" size. > > *Solution:* > I didn't come up with a fix for this issue, seems there is no easy way > to let another instance know this case and reset the > dsnoop->slave_hw_ptr, could you please help? Could you try topic/pcm-direct-resume branch on https://github.com/tiwai/alsa-lib ?? thanks, Takashi