> -----Original Message-----
> From: Wu, Wentong <wentong.wu@xxxxxxxxx>
> Sent: Monday, May 27, 2024 3:39 PM
> To: sakari.ailus@xxxxxxxxxxxxxxx; Winkler, Tomas
> <tomas.winkler@xxxxxxxxx>; gregkh@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; Wu, Wentong <wentong.wu@xxxxxxxxx>;
> stable@xxxxxxxxxxxxxxx; Yao, Hao <hao.yao@xxxxxxxxx>; Chen, Jason Z
> <jason.z.chen@xxxxxxxxx>
> Subject: [PATCH v3] mei: vsc: Don't stop/restart mei device during system
> suspend/resume
>
> The dynamically created mei client device (mei csi) is used as one V4L2 sub
> device of the whole video pipeline, and the V4L2 connection graph is built by
> software node. The mei_stop() and mei_restart() will delete the old mei csi
> client device and create a new mei client device, which will cause the
> software node information saved in old mei csi device lost and the whole
> video pipeline will be broken.
>
> Removing mei_stop()/mei_restart() during system suspend/resume can fix
> the issue above and won't impact hardware actual power saving logic.
>
> Fixes: f6085a96c973 ("mei: vsc: Unregister interrupt handler for system
> suspend")
> Cc: stable@xxxxxxxxxxxxxxx # for 6.8+
> Reported-by: Hao Yao <hao.yao@xxxxxxxxx>
> Signed-off-by: Wentong Wu <wentong.wu@xxxxxxxxx>
> Reviewed-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> Tested-by: Jason Chen <jason.z.chen@xxxxxxxxx>
> Tested-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Acked-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
>
> ---
> Changes since v2:
> - add change log which is not covered by v2, and no code change
>
> Changes since v1:
> - correct Fixes commit id in commit message, and no code change
>
> ---
vX descriptions should go here
> drivers/misc/mei/platform-vsc.c | 39 +++++++++++++--------------------
> 1 file changed, 15 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/misc/mei/platform-vsc.c b/drivers/misc/mei/platform-
> vsc.c index b543e6b9f3cf..1ec65d87488a 100644
> --- a/drivers/misc/mei/platform-vsc.c
> +++ b/drivers/misc/mei/platform-vsc.c
> @@ -399,41 +399,32 @@ static void mei_vsc_remove(struct platform_device
> *pdev)
>
> static int mei_vsc_suspend(struct device *dev) {
> - struct mei_device *mei_dev = dev_get_drvdata(dev);
> - struct mei_vsc_hw *hw = mei_dev_to_vsc_hw(mei_dev);
> + struct mei_device *mei_dev;
> + int ret = 0;
>
> - mei_stop(mei_dev);
> + mei_dev = dev_get_drvdata(dev);
> + if (!mei_dev)
> + return -ENODEV;
>
> - mei_disable_interrupts(mei_dev);
> + mutex_lock(&mei_dev->device_lock);
>
> - vsc_tp_free_irq(hw->tp);
> + if (!mei_write_is_idle(mei_dev))
> + ret = -EAGAIN;
>
> - return 0;
> + mutex_unlock(&mei_dev->device_lock);
> +
> + return ret;
> }
>
> static int mei_vsc_resume(struct device *dev) {
> - struct mei_device *mei_dev = dev_get_drvdata(dev);
> - struct mei_vsc_hw *hw = mei_dev_to_vsc_hw(mei_dev);
> - int ret;
> -
> - ret = vsc_tp_request_irq(hw->tp);
> - if (ret)
> - return ret;
> -
> - ret = mei_restart(mei_dev);
> - if (ret)
> - goto err_free;
> + struct mei_device *mei_dev;
>
> - /* start timer if stopped in suspend */
> - schedule_delayed_work(&mei_dev->timer_work, HZ);
> + mei_dev = dev_get_drvdata(dev);
> + if (!mei_dev)
> + return -ENODEV;
>
> return 0;
> -
> -err_free:
> - vsc_tp_free_irq(hw->tp);
> -
> - return ret;
> }
>
> static DEFINE_SIMPLE_DEV_PM_OPS(mei_vsc_pm_ops, mei_vsc_suspend,
> mei_vsc_resume);
> --
> 2.34.1
