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authorEnrico Granata <egranata@chromium.org>2019-03-07 14:31:50 -0800
committerchrome-bot <chrome-bot@chromium.org>2019-03-21 08:07:25 -0700
commit2a6a9ca09a8d8766b24cd1ba3bc54f2ddc7deaae (patch)
tree7024c4a748246ed30f5b9078f29d4659cc59247c /driver/accelgyro_lsm6dsm.c
parentc272044163c0ca42f4b6649178a015b93ac4307d (diff)
downloadchrome-ec-2a6a9ca09a8d8766b24cd1ba3bc54f2ddc7deaae.tar.gz
driver: lsm6dsm: Fix race condition and sensor labeling issues
This commit fixes two issues with the LSM6DSM driver: - it fixes a race condition in load_fifo() which could lead to samples being labeled at the wrong timestamp if the FIFO was cleared, and a new interrupt occurred, between reading the last sample, and pushing it to the motion sense queue - it drops samples even when the ODR is changed to the same final normalized rate, since the sensor is turned off/on regardless of this condition; additionally, it adds one more sample to the number of samples to be discarded, since I was experimentally seeing occasional spurious data in the first sample after a rate change. BUG=b:124085261 TEST=on Meep with magnetometer stuffed, and CL:1470775 enabled, run CTS sensor test cases Change-Id: I9701d90fa4e86488840b776e2c7afe4dd89570e7 Signed-off-by: Enrico Granata <egranata@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/1509718 Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com> Tested-by: Gwendal Grignou <gwendal@chromium.org> Reviewed-by: Gwendal Grignou <gwendal@chromium.org> Reviewed-by: Diana Z <dzigterman@chromium.org>
Diffstat (limited to 'driver/accelgyro_lsm6dsm.c')
-rw-r--r--driver/accelgyro_lsm6dsm.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/driver/accelgyro_lsm6dsm.c b/driver/accelgyro_lsm6dsm.c
index d7b24a5add..cdf5535c7d 100644
--- a/driver/accelgyro_lsm6dsm.c
+++ b/driver/accelgyro_lsm6dsm.c
@@ -308,6 +308,7 @@ static void push_fifo_data(struct motion_sensor_t *accel, uint8_t *fifo,
static int load_fifo(struct motion_sensor_t *s, const struct fstatus *fsts)
{
+ uint32_t int_ts = last_interrupt_timestamp;
int err, left, length;
uint8_t fifo[FIFO_READ_LEN];
@@ -341,12 +342,13 @@ static int load_fifo(struct motion_sensor_t *s, const struct fstatus *fsts)
return err;
/*
- * Manage patterns and push data. Data should be pushed with the
- * timestamp of the last IRQ before the FIFO was read, so make a
- * copy of the current time in case another interrupt comes in
- * during processing.
+ * Manage patterns and push data. Data is pushed with the
+ * timestamp of the interrupt that got us into this function
+ * in the first place. This avoids a potential race condition
+ * where we empty the FIFO, and a new IRQ comes in between
+ * reading the last sample and pushing it into the FIFO.
*/
- push_fifo_data(s, fifo, length, last_interrupt_timestamp);
+ push_fifo_data(s, fifo, length, int_ts);
left -= length;
} while (left > 0);
@@ -474,7 +476,6 @@ int lsm6dsm_set_data_rate(const struct motion_sensor_t *s, int rate, int rnd)
#ifdef CONFIG_ACCEL_FIFO
const struct motion_sensor_t *accel = LSM6DSM_MAIN_SENSOR(s);
struct lsm6dsm_data *private = LSM6DSM_GET_DATA(accel);
- int old_normalized_rate = data->base.odr;
#endif
int ret = EC_SUCCESS, normalized_rate = 0;
uint8_t ctrl_reg, reg_val = 0;
@@ -533,9 +534,8 @@ int lsm6dsm_set_data_rate(const struct motion_sensor_t *s, int rate, int rnd)
if (ret == EC_SUCCESS) {
data->base.odr = normalized_rate;
#ifdef CONFIG_ACCEL_FIFO
- if (data->base.odr != old_normalized_rate)
- private->samples_to_discard[s->type] =
- LSM6DSM_DISCARD_SAMPLES;
+ private->samples_to_discard[s->type] =
+ LSM6DSM_DISCARD_SAMPLES;
ret = fifo_enable(accel);
if (ret != EC_SUCCESS)
CPRINTS("Failed to enable FIFO. Error: %d", ret);