6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stanislaw Gruszka stanislaw.gruszka@linux.intel.com
commit 2481af79671a6603fce201cbbc48f31e488e9fae upstream.
On some Lenovo platforms, the patch works around problems with ov2740 sensor initialization, which manifest themself like below:
[ 4.540476] ov2740 i2c-INT3474:01: error -EIO: failed to find sensor [ 4.542066] ov2740 i2c-INT3474:01: probe with driver ov2740 failed with error -5
or
[ 7.742633] ov2740 i2c-INT3474:01: chip id mismatch: 2740 != 0 [ 7.742638] ov2740 i2c-INT3474:01: error -ENXIO: failed to find sensor
and also by random failures of video stream start.
Issue can be reproduced by this script:
n=0 k=0 while [ $n -lt 50 ] ; do sudo modprobe -r ov2740 sleep `expr $RANDOM % 5` sudo modprobe ov2740 if media-ctl -p | grep -q ov2740 ; then let k++ fi let n++ done echo Success rate $k/$n
Without the patch, success rate is approximately 15 or 50 tries. With the patch it does not fail.
This problem is some hardware or firmware malfunction, that can not be easy debug and fix. While setting small autosuspend delay is not perfect workaround as user can configure it to any value, it will prevent the failures by default.
Additionally setting small autosuspend delay should have positive effect on power consumption as for most ljca workloads device is used for just a few milliseconds flowed by long periods of at least 100ms of inactivity (usually more).
Fixes: acd6199f195d ("usb: Add support for Intel LJCA device") Cc: stable@vger.kernel.org Reviewed-by: Hans de Goede hdegoede@redhat.com Tested-by: Hans de Goede hdegoede@redhat.com # ThinkPad X1 Yoga Gen 8, ov2740 Acked-by: Sakari Ailus sakari.ailus@linux.intel.com Signed-off-by: Stanislaw Gruszka stanislaw.gruszka@linux.intel.com Link: https://lore.kernel.org/r/20241112075514.680712-2-stanislaw.gruszka@linux.in... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/misc/usb-ljca.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/usb/misc/usb-ljca.c +++ b/drivers/usb/misc/usb-ljca.c @@ -811,6 +811,14 @@ static int ljca_probe(struct usb_interfa if (ret) goto err_free;
+ /* + * This works around problems with ov2740 initialization on some + * Lenovo platforms. The autosuspend delay, has to be smaller than + * the delay after setting the reset_gpio line in ov2740_resume(). + * Otherwise the sensor randomly fails to initialize. + */ + pm_runtime_set_autosuspend_delay(&usb_dev->dev, 10); + usb_enable_autosuspend(usb_dev);
return 0;