From patchwork Fri Sep 23 18:36:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Volker_R=C3=BCmelin?= X-Patchwork-Id: 1681632 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4MZ1V90m7vz1yqW for ; Sat, 24 Sep 2022 04:52:15 +1000 (AEST) Received: from localhost ([::1]:51596 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1obnmX-00032s-57 for incoming@patchwork.ozlabs.org; Fri, 23 Sep 2022 14:52:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40152) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1obnXu-0002ma-1L for qemu-devel@nongnu.org; Fri, 23 Sep 2022 14:37:15 -0400 Received: from mailout01.t-online.de ([194.25.134.80]:57690) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1obnXs-0005GE-26 for qemu-devel@nongnu.org; Fri, 23 Sep 2022 14:37:05 -0400 Received: from fwd72.dcpf.telekom.de (fwd72.aul.t-online.de [10.223.144.98]) by mailout01.t-online.de (Postfix) with SMTP id 110CA5E3E; Fri, 23 Sep 2022 20:36:50 +0200 (CEST) Received: from linpower.localnet ([84.175.228.229]) by fwd72.t-online.de with (TLSv1.3:TLS_AES_256_GCM_SHA384 encrypted) esmtp id 1obnXb-4Ns8yP0; Fri, 23 Sep 2022 20:36:48 +0200 Received: by linpower.localnet (Postfix, from userid 1000) id 9B2F2200619; Fri, 23 Sep 2022 20:36:40 +0200 (CEST) From: =?utf-8?q?Volker_R=C3=BCmelin?= To: Gerd Hoffmann Cc: qemu-devel@nongnu.org, Christian Schoenebeck Subject: [PATCH 04/12] alsaaudio: reduce playback latency Date: Fri, 23 Sep 2022 20:36:32 +0200 Message-Id: <20220923183640.8314-4-vr_qemu@t-online.de> X-Mailer: git-send-email 2.35.3 In-Reply-To: <38d7417a-fc26-be39-6a63-99c79ee15fc9@t-online.de> References: <38d7417a-fc26-be39-6a63-99c79ee15fc9@t-online.de> MIME-Version: 1.0 X-TOI-EXPURGATEID: 150726::1663958208-01449CE0-C5FB84A3/0/0 CLEAN NORMAL X-TOI-MSGID: 91c864bd-03a1-4816-8257-b481ae4fc39c Received-SPF: none client-ip=194.25.134.80; envelope-from=volker.ruemelin@t-online.de; helo=mailout01.t-online.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Change the buffer_get_free pcm_ops function to report the free ALSA playback buffer. The generic buffer becomes a temporary buffer and is empty after a call to audio_run_out(). Signed-off-by: Volker Rümelin Acked-by: Marc-André Lureau --- audio/alsaaudio.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/audio/alsaaudio.c b/audio/alsaaudio.c index 4a61378cd7..7a2a94cd42 100644 --- a/audio/alsaaudio.c +++ b/audio/alsaaudio.c @@ -602,6 +602,42 @@ static int alsa_open(bool in, struct alsa_params_req *req, return -1; } +static size_t alsa_buffer_get_free(HWVoiceOut *hw) +{ + ALSAVoiceOut *alsa = (ALSAVoiceOut *)hw; + snd_pcm_sframes_t avail; + size_t alsa_free, generic_free, generic_in_use; + + avail = snd_pcm_avail_update(alsa->handle); + if (avail < 0) { + if (avail == -EPIPE) { + if (!alsa_recover(alsa->handle)) { + avail = snd_pcm_avail_update(alsa->handle); + } + } + if (avail < 0) { + alsa_logerr(avail, + "Could not obtain number of available frames\n"); + avail = 0; + } + } + + alsa_free = avail * hw->info.bytes_per_frame; + generic_free = audio_generic_buffer_get_free(hw); + generic_in_use = hw->samples * hw->info.bytes_per_frame - generic_free; + if (generic_in_use) { + /* + * This code can only be reached in the unlikely case that + * snd_pcm_avail_update() returned a larger number of frames + * than snd_pcm_writei() could write. Make sure that all + * remaining bytes in the generic buffer can be written. + */ + alsa_free = alsa_free > generic_in_use ? alsa_free - generic_in_use : 0; + } + + return alsa_free; +} + static size_t alsa_write(HWVoiceOut *hw, void *buf, size_t len) { ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw; @@ -916,7 +952,7 @@ static struct audio_pcm_ops alsa_pcm_ops = { .init_out = alsa_init_out, .fini_out = alsa_fini_out, .write = alsa_write, - .buffer_get_free = audio_generic_buffer_get_free, + .buffer_get_free = alsa_buffer_get_free, .run_buffer_out = audio_generic_run_buffer_out, .enable_out = alsa_enable_out,