From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 46CEA2C1A5; Mon, 12 Aug 2024 16:32:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723480339; cv=none; b=TirB997PoXRUkGTcrqUOw0R/PGbVpUMCtE5oV7unfU53Viy/thKIM/J/0vZqO67IMtaIywackC0kTbwf/aSqltdY4ncPJFk1enOVg4FpCgbbFjsOEdeO95v1ge+EOo4/p6g3A0h6PfUs8mb4+wCxWB5Kzbkr2IA+Q1nCyxxJxxU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723480339; c=relaxed/simple; bh=MJlT0KddbSSSTTv3AxhQfq0LelwZ9a0JZRmnQumoabY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WXRMXiFcWXgzdvWkt/TN6afMS/bCXKN6dabvgvjkRRNqQWxYvYSCfDuj38rvwvTnz+vJAbG3AIGs2Nm9wRE9at/sSIeBZ3M33pIDaeYTwrCuYIasW1StEhFQ6IUImdSnA08HPUcLD8FaCEVYiSjGuCIF2lim5jhk9CdHPbVpyBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UPj+qfG8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="UPj+qfG8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44541C32782; Mon, 12 Aug 2024 16:32:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723480338; bh=MJlT0KddbSSSTTv3AxhQfq0LelwZ9a0JZRmnQumoabY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UPj+qfG8NJtoie4DI2pQWFDtGEsTBwHccoQkdr4EbhCjHryw4opyWiJ1yi7k1y2jj UXLxg5xqy0WS5pKGC4WalMPwt5fp4mHBsDb3mNOUup90M6YHMiDyH4cnuxSdbgMVr6 ON/DUowC8ugKmFnGyAh1wl+L1t+0h3JJt0/jy3Qc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Arseniy Krasnov , Sebastian Andrzej Siewior , Jerome Brunet , Mark Brown , Sasha Levin Subject: [PATCH 6.10 168/263] ASoC: meson: axg-fifo: fix irq scheduling issue with PREEMPT_RT Date: Mon, 12 Aug 2024 18:02:49 +0200 Message-ID: <20240812160152.978792970@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240812160146.517184156@linuxfoundation.org> References: <20240812160146.517184156@linuxfoundation.org> User-Agent: quilt/0.67 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 6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jerome Brunet [ Upstream commit 5003d0ce5c7da3a02c0aff771f516f99731e7390 ] With PREEMPT_RT enabled a spinlock_t becomes a sleeping lock. This is usually not a problem with spinlocks used in IRQ context since IRQ handlers get threaded. However, if IRQF_ONESHOT is set, the primary handler won't be force-threaded and runs always in hardirq context. This is a problem because spinlock_t requires a preemptible context on PREEMPT_RT. In this particular instance, regmap mmio uses spinlock_t to protect the register access and IRQF_ONESHOT is set on the IRQ. In this case, it is actually better to do everything in threaded handler and it solves the problem with PREEMPT_RT. Reported-by: Arseniy Krasnov Closes: https://lore.kernel.org/linux-amlogic/20240729131652.3012327-1-avkrasnov@salutedevices.com Suggested-by: Sebastian Andrzej Siewior Fixes: b11d26660dff ("ASoC: meson: axg-fifo: use threaded irq to check periods") Signed-off-by: Jerome Brunet Reviewed-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20240807162705.4024136-1-jbrunet@baylibre.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- sound/soc/meson/axg-fifo.c | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-) diff --git a/sound/soc/meson/axg-fifo.c b/sound/soc/meson/axg-fifo.c index 59abe0b3c59fb..486c56a84552d 100644 --- a/sound/soc/meson/axg-fifo.c +++ b/sound/soc/meson/axg-fifo.c @@ -207,25 +207,18 @@ static irqreturn_t axg_fifo_pcm_irq_block(int irq, void *dev_id) status = FIELD_GET(STATUS1_INT_STS, status); axg_fifo_ack_irq(fifo, status); - /* Use the thread to call period elapsed on nonatomic links */ - if (status & FIFO_INT_COUNT_REPEAT) - return IRQ_WAKE_THREAD; + if (status & ~FIFO_INT_COUNT_REPEAT) + dev_dbg(axg_fifo_dev(ss), "unexpected irq - STS 0x%02x\n", + status); - dev_dbg(axg_fifo_dev(ss), "unexpected irq - STS 0x%02x\n", - status); + if (status & FIFO_INT_COUNT_REPEAT) { + snd_pcm_period_elapsed(ss); + return IRQ_HANDLED; + } return IRQ_NONE; } -static irqreturn_t axg_fifo_pcm_irq_block_thread(int irq, void *dev_id) -{ - struct snd_pcm_substream *ss = dev_id; - - snd_pcm_period_elapsed(ss); - - return IRQ_HANDLED; -} - int axg_fifo_pcm_open(struct snd_soc_component *component, struct snd_pcm_substream *ss) { @@ -251,8 +244,9 @@ int axg_fifo_pcm_open(struct snd_soc_component *component, if (ret) return ret; - ret = request_threaded_irq(fifo->irq, axg_fifo_pcm_irq_block, - axg_fifo_pcm_irq_block_thread, + /* Use the threaded irq handler only with non-atomic links */ + ret = request_threaded_irq(fifo->irq, NULL, + axg_fifo_pcm_irq_block, IRQF_ONESHOT, dev_name(dev), ss); if (ret) return ret; -- 2.43.0