linux-kernel - [PATCH] ASoC: fsl_sai: Remove unnecessary FIFO reset in ISR

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Date:   Wed, 17 Aug 2022 13:24:27 +0800
From:   Shengjiu Wang <shengjiu.wang@....com>
To:     nicoleotsuka@...il.com, Xiubo.Lee@...il.com, festevam@...il.com,
        shengjiu.wang@...il.com, lgirdwood@...il.com, broonie@...nel.org,
        perex@...ex.cz, tiwai@...e.com, alsa-devel@...a-project.org
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH] ASoC: fsl_sai: Remove unnecessary FIFO reset in ISR

The FIFO reset drops the words in the FIFO, which may cause
channel swap when SAI module is running, especially when the
DMA speed is low. So it is not good to do FIFO reset in ISR,
then remove the operation.

Fixes: e2681a1bf5ae ("ASoC: fsl_sai: Add isr to deal with error flag")
Signed-off-by: Shengjiu Wang <shengjiu.wang@....com>
---
 sound/soc/fsl/fsl_sai.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index d430eece1d6b..a7fa6f0bf83d 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -114,11 +114,8 @@ static irqreturn_t fsl_sai_isr(int irq, void *devid)
 	if (flags & FSL_SAI_CSR_SEF)
 		dev_dbg(dev, "isr: Tx Frame sync error detected\n");
 
-	if (flags & FSL_SAI_CSR_FEF) {
+	if (flags & FSL_SAI_CSR_FEF)
 		dev_dbg(dev, "isr: Transmit underrun detected\n");
-		/* FIFO reset for safety */
-		xcsr |= FSL_SAI_CSR_FR;
-	}
 
 	if (flags & FSL_SAI_CSR_FWF)
 		dev_dbg(dev, "isr: Enabled transmit FIFO is empty\n");
@@ -148,11 +145,8 @@ static irqreturn_t fsl_sai_isr(int irq, void *devid)
 	if (flags & FSL_SAI_CSR_SEF)
 		dev_dbg(dev, "isr: Rx Frame sync error detected\n");
 
-	if (flags & FSL_SAI_CSR_FEF) {
+	if (flags & FSL_SAI_CSR_FEF)
 		dev_dbg(dev, "isr: Receive overflow detected\n");
-		/* FIFO reset for safety */
-		xcsr |= FSL_SAI_CSR_FR;
-	}
 
 	if (flags & FSL_SAI_CSR_FWF)
 		dev_dbg(dev, "isr: Enabled receive FIFO is full\n");
-- 
2.34.1