The cros_ec_spi transfer had two problems with its timeout code:
1. It looked at the timeout even in the case that it found valid data.
2. If the cros_ec_spi code got switched out for a while, it's possible
it could get a timeout after a single loop. Let's be paranoid and
make sure we do one last transfer after the timeout expires.
Signed-off-by: Doug Anderson <diand...@chromium.org>
Acked-by: Lee Jones <lee.jo...@linaro.org>
Reviewed-by: Simon Glass <s...@chromium.org>
Tested-by: Andrew Bresticker <abres...@chromium.org>
Tested-by: Stephen Warren <swar...@nvidia.com>
---
Changes in v3: None
Changes in v2: None
drivers/mfd/cros_ec_spi.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index a2a605d..4f863c3 100644
--- a/drivers/mfd/cros_ec_spi.c
+++ b/drivers/mfd/cros_ec_spi.c
@@ -113,7 +113,9 @@ static int cros_ec_spi_receive_response(struct
cros_ec_device *ec_dev,
/* Receive data until we see the header byte */
deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
- do {
+ while (true) {
+ unsigned long start_jiffies = jiffies;
+
memset(&trans, 0, sizeof(trans));
trans.cs_change = 1;
trans.rx_buf = ptr = ec_dev->din;
@@ -134,12 +136,19 @@ static int cros_ec_spi_receive_response(struct
cros_ec_device *ec_dev,
break;
}
}
+ if (ptr != end)
+ break;
- if (time_after(jiffies, deadline)) {
+ /*
+ * Use the time at the start of the loop as a timeout. This
+ * gives us one last shot at getting the transfer and is useful
+ * in case we got context switched out for a while.
+ */
+ if (time_after(start_jiffies, deadline)) {
dev_warn(ec_dev->dev, "EC failed to respond in time\n");
return -ETIMEDOUT;
}
- } while (ptr == end);
+ }
/*
* ptr now points to the header byte. Copy any valid data to the
--
1.9.1.423.g4596e3a
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