Linux kernel -stable discussions
 help / color / mirror / Atom feed
* FAILED: patch "[PATCH] iio: imu: inv_icm42600: fix timestamping by limiting FIFO" failed to apply to 5.15-stable tree
@ 2026-07-13 12:49 gregkh
  2026-07-14  1:16 ` [PATCH 5.15.y 1/8] iio: imu: inv_icm42600: make timestamp module chip independent Sasha Levin
  0 siblings, 1 reply; 9+ messages in thread
From: gregkh @ 2026-07-13 12:49 UTC (permalink / raw)
  To: jean-baptiste.maneyrol, jic23; +Cc: stable


The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x affe3f077d7a4eeb25937f5323ff059a54b4712c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071317-refill-huntress-d0e2@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From affe3f077d7a4eeb25937f5323ff059a54b4712c Mon Sep 17 00:00:00 2001
From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Date: Mon, 29 Jun 2026 21:51:55 +0200
Subject: [PATCH] iio: imu: inv_icm42600: fix timestamping by limiting FIFO
 reading

Timestamps are made by measuring the chip clock using the watermark
interrupts. If we read more than watermark samples as done today, we
are reducing the period between interrupts and distort the time
measurement. Fix that by reading only watermark samples in the
interrupt case.

Fixes: 7f85e42a6c54 ("iio: imu: inv_icm42600: add buffer support in iio devices")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
index 68a395758031..5c3840acf085 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
@@ -248,6 +248,7 @@ int inv_icm42600_buffer_update_watermark(struct inv_icm42600_state *st)
 
 	/* compute watermark value in bytes */
 	wm_size = watermark * packet_size;
+	st->fifo.watermark.value = watermark;
 
 	/* changing FIFO watermark requires to turn off watermark interrupt */
 	ret = regmap_update_bits_check(st->map, INV_ICM42600_REG_INT_SOURCE0,
@@ -454,11 +455,10 @@ int inv_icm42600_buffer_fifo_read(struct inv_icm42600_state *st,
 	st->fifo.nb.accel = 0;
 	st->fifo.nb.total = 0;
 
-	/* compute maximum FIFO read size */
+	/* compute maximum FIFO read size (watermark for max = 0 interrupt case) */
 	if (max == 0)
-		max_count = sizeof(st->fifo.data);
-	else
-		max_count = max * inv_icm42600_get_packet_size(st->fifo.en);
+		max = st->fifo.watermark.value;
+	max_count = max * inv_icm42600_get_packet_size(st->fifo.en);
 
 	/* read FIFO count value */
 	raw_fifo_count = (__be16 *)st->buffer;
@@ -574,6 +574,7 @@ int inv_icm42600_buffer_init(struct inv_icm42600_state *st)
 
 	st->fifo.watermark.eff_gyro = 1;
 	st->fifo.watermark.eff_accel = 1;
+	st->fifo.watermark.value = 1;
 
 	/*
 	 * Default FIFO configuration (bits 7 to 5)
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
index ffca4da1e249..88b8b9f780af 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
@@ -34,6 +34,7 @@ struct inv_icm42600_fifo {
 		unsigned int accel;
 		unsigned int eff_gyro;
 		unsigned int eff_accel;
+		unsigned int value;
 	} watermark;
 	size_t count;
 	struct {


^ permalink raw reply related	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2026-07-14  1:16 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-07-13 12:49 FAILED: patch "[PATCH] iio: imu: inv_icm42600: fix timestamping by limiting FIFO" failed to apply to 5.15-stable tree gregkh
2026-07-14  1:16 ` [PATCH 5.15.y 1/8] iio: imu: inv_icm42600: make timestamp module chip independent Sasha Levin
2026-07-14  1:16   ` [PATCH 5.15.y 2/8] iio: move inv_icm42600 timestamp module in common Sasha Levin
2026-07-14  1:16   ` [PATCH 5.15.y 3/8] iio: make invensense timestamp module generic Sasha Levin
2026-07-14  1:16   ` [PATCH 5.15.y 4/8] iio: imu: inv_mpu6050: use the common inv_sensors timestamp module Sasha Levin
2026-07-14  1:16   ` [PATCH 5.15.y 5/8] iio: invensense: remove redundant initialization of variable period Sasha Levin
2026-07-14  1:16   ` [PATCH 5.15.y 6/8] iio: invensense: fix timestamp glitches when switching frequency Sasha Levin
2026-07-14  1:16   ` [PATCH 5.15.y 7/8] iio: imu: inv_icm42600: stabilized timestamp in interrupt Sasha Levin
2026-07-14  1:16   ` [PATCH 5.15.y 8/8] iio: imu: inv_icm42600: fix timestamping by limiting FIFO reading Sasha Levin

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox