From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D827E18A93F; Sat, 12 Sep 2026 14:25:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789223160; cv=none; b=AyVgZS0Kfnf7Bsw/7rJ2TS4YeODvz/qMJkr4cVHnlBOxTS6mT2H7IfJU6udS113C1JMi0BuRsAgW5uvTtQO4o4WRTCSgkJiBdv3gSb53MBLOU2iuYJXI+ZoPdYEh4EG6Qrwpq4pICkpD9uwte1ivrQUj3USGsk/hkFKw+RcImF8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789223160; c=relaxed/simple; bh=HzhyjUgBmFibDpkY3OrqPAOtCjEWWBs4dK6rVH3Yv24=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AN9Td+s/XqBTGfrJkdc+U1SdukXkPsmk/qETFgm5FFDR8cPHfy7B+PTpDs5XItvSt1IpWv7WdMUgkyqGlmIxsNmETx0e49f1k3wSfdg4izxJqgnE5ORiA4BfFiOETYBiqwu5F5+o7yaCP475IaG+dCIPdPuEyqZk1vfRhdZt/9w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wMEXfQH+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wMEXfQH+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91D771F000FF; Sat, 12 Sep 2026 14:25:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789223159; bh=isLdnANLs7NNzTr+Yh4NEN5EhqElS5qNGQ7ZkV27aK0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=wMEXfQH+r+4irABJgaZ0jdrS03ldd4hWo5gTwMgvh2/95cJAy4xla4ZbpiijeH6WS HF/43CY25y39ehdevQw9FCWKiHC/V8Fq2LSPbM9pqYZYIodYehb5Aoh3f9yaFhN6Bo D8U1PslwL1nrrJY5rHMhgDTtG1Rkm2MTRqwsAMIU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, James Calligeros , Mark Brown , Sasha Levin Subject: [PATCH 6.6 0734/1424] ASoC: apple: mca: increase SERDES reset delay Date: Sat, 12 Sep 2026 08:52:46 +0200 Message-ID: <20260912065623.734703718@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Calligeros [ Upstream commit cccd721e5aab03e92234faee72b363c9ba60611c ] The SERDES clusters in this peripheral take a long time to warm up. We tried polling the reset bit until cleared, however this is not a reliable signal of readiness to be configured. Only waiting ~25 us to give the cluster a chance to settle makes it work reliably. Increase the 2 us delay to 25 us and hope we never have to do this again. Fixes: d8b3e396088d ("ASoC: apple: mca: Fix SERDES reset sequence") Signed-off-by: James Calligeros Link: https://patch.msgid.link/20260711-apple-audio-redux-v4-1-2994d87c2f24@gmail.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- sound/soc/apple/mca.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sound/soc/apple/mca.c b/sound/soc/apple/mca.c index 0e96caa607fb8..88d6de6bdbc43 100644 --- a/sound/soc/apple/mca.c +++ b/sound/soc/apple/mca.c @@ -210,10 +210,10 @@ static void mca_fe_early_trigger(struct snd_pcm_substream *substream, int cmd, SERDES_STATUS_EN | SERDES_STATUS_RST, SERDES_STATUS_RST); /* - * Experiments suggest that it takes at most ~1 us - * for the bit to clear, so wait 2 us for good measure. + * The SERDES cluster needs a bit of time to reset itself + * and settle before we start poking it. This is... slow... */ - udelay(2); + udelay(25); WARN_ON(readl_relaxed(cl->base + serdes_unit + REG_SERDES_STATUS) & SERDES_STATUS_RST); mca_modify(cl, serdes_conf, SERDES_CONF_SYNC_SEL, -- 2.53.0