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From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Laxman Dewangan <ldewangan@nvidia.com>,
	Mikko Perttunen <cyndis@kapsi.fi>,
	Wolfram Sang <wsa@the-dreams.de>
Cc: linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v5 8/8] i2c: tegra: Check DMA completion status in addition to left time
Date: Tue, 14 Jan 2020 04:34:42 +0300	[thread overview]
Message-ID: <20200114013442.28448-9-digetx@gmail.com> (raw)
In-Reply-To: <20200114013442.28448-1-digetx@gmail.com>

It is more robust to check completion status in addition to the left time
in a case of DMA transfer because transfer's completion happens in two
phases [one is ISR, other is tasklet] and thus it is possible that DMA is
completed while I2C completion awaiting times out because of the deferred
notification done by the DMA driver. The DMA completion status becomes
100% actual after DMA synchronization. This fixes spurious DMA timeouts
when system is under load.

Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 3c7c86d4b0e4..cbc2ad49043e 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1224,7 +1224,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 					 i2c_dev->rx_dma_chan :
 					 i2c_dev->tx_dma_chan);
 
-		if (time_left == 0) {
+		if (!time_left && !completion_done(&i2c_dev->dma_complete)) {
 			dev_err(i2c_dev->dev, "DMA transfer timeout\n");
 			tegra_i2c_init(i2c_dev, true);
 			return -ETIMEDOUT;
-- 
2.24.0


  parent reply	other threads:[~2020-01-14  1:37 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14  1:34 [PATCH v5 0/8] NVIDIA Tegra I2C driver fixes and improvements Dmitry Osipenko
2020-01-14  1:34 ` [PATCH v5 1/8] i2c: tegra: Fix suspending in active runtime PM state Dmitry Osipenko
2020-01-15 17:33   ` Wolfram Sang
2020-01-14  1:34 ` [PATCH v5 2/8] i2c: tegra: Properly disable runtime PM on driver's probe error Dmitry Osipenko
2020-01-15 17:34   ` Wolfram Sang
2020-01-14  1:34 ` [PATCH v5 3/8] i2c: tegra: Prevent interrupt triggering after transfer timeout Dmitry Osipenko
2020-01-14  1:34 ` [PATCH v5 4/8] i2c: tegra: Support atomic transfers Dmitry Osipenko
2020-01-14  1:34 ` [PATCH v5 5/8] i2c: tegra: Rename I2C_PIO_MODE_MAX_LEN to I2C_PIO_MODE_PREFERRED_LEN Dmitry Osipenko
2020-01-14  1:34 ` [PATCH v5 6/8] i2c: tegra: Use relaxed versions of readl/writel Dmitry Osipenko
2020-01-14  1:34 ` [PATCH v5 7/8] i2c: tegra: Always terminate DMA transfer Dmitry Osipenko
2020-01-14  1:34 ` Dmitry Osipenko [this message]
2020-01-15 17:35 ` [PATCH v5 0/8] NVIDIA Tegra I2C driver fixes and improvements Wolfram Sang
2020-01-16 16:38   ` Dmitry Osipenko

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