Hi Wentong,
Thanks for the patch. I thought something like this would indeed have been
possible.
On Thu, May 16, 2024 at 09:54:00AM +0800, Wentong Wu wrote:
> 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: 386a766c4169 ("mei: Add MEI hardware support for IVSC device")
I think this should be instead:
Fixes: f6085a96c973 ("mei: vsc: Unregister interrupt handler for system suspend")
As this fix depends on the previous not-quite-as-good fix.
Reviewed-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Tested-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # for 6.8+
> Reported-by: Hao Yao <hao.yao@xxxxxxxxx>
> Signed-off-by: Wentong Wu <wentong.wu@xxxxxxxxx>
> Tested-by: Jason Chen <jason.z.chen@xxxxxxxxx>
> ---
> 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);
--
Kind regards,
Sakari Ailus
