[PATCH] usb: xhci-mtk: fixup mouse wakeup failure during system suspend

[chunfeng.yun@mediatek.com (chunfeng yun)]

Hi Mathias,

On Thu, 2016-04-21 at 10:04 +0800, Chunfeng Yun wrote:
> Click mouse after xhci suspend completion but before system suspend
> completion, system will not be waken up by mouse if the duration of
> them is larger than 20ms which is the device UFP's resume signaling
> lasted. Another reason is that the SPM is not enabled before system
> suspend compeltion, this causes SPM also not notice the resume signal.
> So in order to reduce the duration less than 20ms, make use of
> syscore's suspend/resume interface.
> In fact it is a work around solution which only reduces the
> probability of failure, because we can't ensure that the duration from
> syscore's suspend completion to SPM working is always less than 20ms.
> 
> Because the syscore runs on irq disabled context, and xhci's
> suspend/resume calls some sleeping functions, enable local irq
> and then disable it during suspend/resume. This may be not a problem,
> since only boot CPU is runing.
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> ---
>  drivers/usb/host/xhci-mtk.c |   31 ++++++++++++++++++++++++++++++-
>  1 file changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
> index 79959f1..8277f02 100644
> --- a/drivers/usb/host/xhci-mtk.c
> +++ b/drivers/usb/host/xhci-mtk.c
> @@ -28,6 +28,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/regmap.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/syscore_ops.h>
>  
>  #include "xhci.h"
>  #include "xhci-mtk.h"
> @@ -490,6 +491,8 @@ static int xhci_mtk_setup(struct usb_hcd *hcd)
>  	return xhci_gen_setup(hcd, xhci_mtk_quirks);
>  }
>  
> +static struct device *xhci_mtk_syscore_dev;
> +
>  static int xhci_mtk_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -512,6 +515,7 @@ static int xhci_mtk_probe(struct platform_device *pdev)
>  	if (!mtk)
>  		return -ENOMEM;
>  
> +	xhci_mtk_syscore_dev = dev;
>  	mtk->dev = dev;
>  	mtk->vbus = devm_regulator_get(dev, "vbus");
>  	if (IS_ERR(mtk->vbus)) {
> @@ -740,6 +744,29 @@ static int __maybe_unused xhci_mtk_resume(struct device *dev)
>  	return 0;
>  }
>  
> +static int xhci_mtk_syscore_suspend(void)
> +{
> +	local_irq_enable();
> +	xhci_mtk_suspend(xhci_mtk_syscore_dev);
> +	local_irq_disable();
> +
> +	return 0;
> +}
> +
> +static void xhci_mtk_syscore_resume(void)
> +{
> +	local_irq_enable();
> +	xhci_mtk_resume(xhci_mtk_syscore_dev);
> +	local_irq_disable();
> +
> +	return;
> +}
> +
> +static struct syscore_ops xhci_mtk_syscore_ops = {
> +	.suspend = xhci_mtk_syscore_suspend,
> +	.resume = xhci_mtk_syscore_resume,
> +};
> +
>  static const struct dev_pm_ops xhci_mtk_pm_ops = {
>  	SET_SYSTEM_SLEEP_PM_OPS(xhci_mtk_suspend, xhci_mtk_resume)
>  };
> @@ -758,7 +785,7 @@ static struct platform_driver mtk_xhci_driver = {
>  	.remove	= xhci_mtk_remove,
>  	.driver	= {
>  		.name = "xhci-mtk",
> -		.pm = DEV_PM_OPS,
> +		/*.pm = DEV_PM_OPS,*/
>  		.of_match_table = of_match_ptr(mtk_xhci_of_match),
>  	},
>  };
> @@ -766,6 +793,7 @@ MODULE_ALIAS("platform:xhci-mtk");
>  
>  static int __init xhci_mtk_init(void)
>  {
> +	register_syscore_ops(&xhci_mtk_syscore_ops);
>  	xhci_init_driver(&xhci_mtk_hc_driver, &xhci_mtk_overrides);
>  	return platform_driver_register(&mtk_xhci_driver);
>  }
> @@ -774,6 +802,7 @@ module_init(xhci_mtk_init);
>  static void __exit xhci_mtk_exit(void)
>  {
>  	platform_driver_unregister(&mtk_xhci_driver);
> +	unregister_syscore_ops(&xhci_mtk_syscore_ops);
>  }
>  module_exit(xhci_mtk_exit);

Do you have any suggestions about the patch?

Thanks
>