From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794591475; b=mWbf6jHNuragZ6H+WwtBMZXY1BfbntG1xsgLA2VCvn1oyA3g0p2Ths/ePznGcfY94YGS ASaUoQ2w6C+1rA/5mxc4gTU/MGsFniTw2mYCkmxhRoCHHBcdTlw5J0tnYJ/1Ka737VyQD cG7pS5X6nTMK2L5qddzJltwghiLZFwgWSGD1B6kKpsnejK3FF3aWdFKYFhf2d6i3IgcNj Xbqyv5uvHOCioo5BlOCu1bDzrjupxiJj8UcNJFebvP5YywH5Dy140FyEws6CSB8ewRC7S 1ItxIJP4m8wr//wDjDlB6mIb+fgFsrioz8oocE3b451tPh0NrZrVzrjagJbTyOBqEvA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591475; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=h5MzLMSF+HPXTy1N2eixDpOBi0VoWWs8p+H88bCGHL8=; b=mWwBvQVA5FxUg/HUMfYCqOBTvbW+kZ6DTY9s1ciqjYqRz+gHEzamcm+AnkubURYIX6fr h67XLlYrYR9U01nfHpchSUpRkdLFSFTzY7ld25Fs9p+P+dzWUYe3r/YNBa9S2iYkkV5/n qDqsBnXScSHfxbxteM3fUye+aGQYgg7vtgASZpoooDmfMhymgWdCz5L2BRFqR48Yzy7z/ OQA2BrCPZgPPc1gZNWfBA/J7oTqn4NcwVeArMdsoVULDE7ytD9y49bM/NUQytCRRlAWLQ NV00aSzU36ChgbbYuomloqB7BAHwq98z0PQ1kL+Ar+zzMQSavUtRk0eetw5oZzYUAZg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=xlYX6FJZ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BFB25606E212; Fri, 13 Nov 2026 17:37:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=xlYX6FJZ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D5531F000C4; Fri, 13 Nov 2026 17:37:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591475; bh=h5MzLMSF+HPXTy1N2eixDpOBi0VoWWs8p+H88bCGHL8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xlYX6FJZhR0dEtGrfec6X7u53sdwf2qrfcy3dqSktirla/XnVcZn/shqf4ghOCwe9 T9kMci+1IP4yn8M6xUBOtsBpC6H2qodjUqLUShfJBVrb6SotjJpfv6dQhhtoZgtfrK wlSNQ7a00VjVDiwCURrTk8svuli3+jzpnSzxlx/0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vladyslav Tymoshchuk , Srinivas Kandagatla , Mark Brown , Sasha Levin Subject: [PATCH 6.12 557/670] ASoC: qcom: q6apm-dai: wrap the position of a full ring to 0 Date: Fri, 13 Nov 2026 10:52:01 -0500 Message-ID: <20261113153830.761102639@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vladyslav Tymoshchuk [ Upstream commit 0ea3e0b196f9dcc17b40ac881a6efef06459975b ] q6apm_dai_pointer() turns the number of period buffers the DSP has returned in the current lap, 1..periods, into a position and reports one frame less than that. Commit a93dad6f4e6a ("ASoC: q6apm-dai: make use of q6apm_get_hw_pointer") added the "- 1" so that the end of the ring is not reported as a position equal to the buffer size. One frame short has a cost once the application stops feeding the stream. The DSP returns the last queued buffer and the position stops at appl_ptr - 1, so avail stays at buffer_size - 1, below the default stop_threshold. The DSP sends nothing more as its queue is empty, so no period interrupt comes either: ALSA never detects the underrun and the stream stays RUNNING. A poll-driven application that missed its last wakeup waits forever, and drain only ends on its timeout, with -EIO. On capture, the last frame of each period is held back until the next one. Before that commit the position wrapped to 0 at the end of the ring. Do that again. A full lap is the start of the ring, and snd_pcm_update_hw_ptr0() accounts for the wrap: the position cannot move by more than one lap between two updates, as each returned buffer calls snd_pcm_period_elapsed() and the DSP holds at most periods buffers. Seen on a OnePlus Pad 3 (SM8750) with PipeWire in interrupt-driven scheduling: after a stall the PCM sat at hw_ptr 78239, appl_ptr 78240 (avail 3839 of 3840) for two hours. Fixes: a93dad6f4e6a ("ASoC: q6apm-dai: make use of q6apm_get_hw_pointer") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-5-5 Signed-off-by: Vladyslav Tymoshchuk Reviewed-by: Srinivas Kandagatla Tested-by: Srinivas Kandagatla Link: https://patch.msgid.link/20261014162703.10172-2-tvlad744@gmail.com Signed-off-by: Mark Brown [ sashal: adjusted context in q6apm_dai_pointer() because the preceding bytes_to_frames() branch is absent ] Signed-off-by: Sasha Levin --- sound/soc/qcom/qdsp6/q6apm-dai.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/sound/soc/qcom/qdsp6/q6apm-dai.c b/sound/soc/qcom/qdsp6/q6apm-dai.c index 3b00c6d5174ab..fef69e4318908 100644 --- a/sound/soc/qcom/qdsp6/q6apm-dai.c +++ b/sound/soc/qcom/qdsp6/q6apm-dai.c @@ -441,11 +441,15 @@ static snd_pcm_uframes_t q6apm_dai_pointer(struct snd_soc_component *component, struct q6apm_dai_rtd *prtd = runtime->private_data; snd_pcm_uframes_t ptr; - ptr = q6apm_get_hw_pointer(prtd->graph, substream->stream) * runtime->period_size; - if (ptr) - return ptr - 1; + /* + * The hw pointer counts the period buffers the DSP has returned in + * this lap, 1..periods. A full lap is the start of the ring again: + * report 0 rather than one frame less, so that the position of a + * drained buffer reaches appl_ptr and ALSA sees the underrun. + */ + ptr = q6apm_get_hw_pointer(prtd->graph, substream->stream) % runtime->periods; - return 0; + return ptr * runtime->period_size; } static int q6apm_dai_hw_params(struct snd_soc_component *component, -- 2.53.0