On Fri, Sep 02, 2022 at 02:36:39PM +0800, Yinbo Zhu wrote:
> The ohci retaining bogus hardware states cause usb disconnect devices
> connected before hibernation(s4), this issue occur when ohci-platform
> driver build as a module and the built-in ohci-platform driver will
> re probe and re enumerate the devices, so there will be no such problem.
>
> Avoid retaining bogus hardware states during resume-from-hibernation.
> Previously we had reset the hardware as part of preparing to reinstate
> the snapshot image. But we can do better now with the new PM framework,
> since we know exactly which resume operations are from hibernation.
>
> According to the commit 'cd1965db054e ("USB: ohci: move ohci_pci_{
> suspend,resume} to ohci-hcd.c")' and commit '6ec4beb5c701 ("USB: new
> flag for resume-from-hibernation")', the flag "hibernated" is for
> resume-from-hibernation and it should be true when usb resume from disk.
>
> When this flag "hibernated" is set, the drivers will reset the hardware
> to get rid of any existing state and make sure resume from hibernation
> re-enumerates everything for ohci.
>
> Signed-off-by: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
> ---
> Change in v4:
> Add explain what this disconnect issue is.
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
I'm a little surprised that the driver doesn't support runtime PM.
> drivers/usb/host/ohci-platform.c | 28 ++++++++++++++++++++++++----
> 1 file changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/host/ohci-platform.c b/drivers/usb/host/ohci-platform.c
> index 0adae6265127..822a0f927e62 100644
> --- a/drivers/usb/host/ohci-platform.c
> +++ b/drivers/usb/host/ohci-platform.c
> @@ -289,7 +289,7 @@ static int ohci_platform_suspend(struct device *dev)
> return ret;
> }
>
> -static int ohci_platform_resume(struct device *dev)
> +static int ohci_platform_resume_common(struct device *dev, bool hibernated)
> {
> struct usb_hcd *hcd = dev_get_drvdata(dev);
> struct usb_ohci_pdata *pdata = dev_get_platdata(dev);
> @@ -301,7 +301,7 @@ static int ohci_platform_resume(struct device *dev)
> return err;
> }
>
> - ohci_resume(hcd, false);
> + ohci_resume(hcd, hibernated);
>
> pm_runtime_disable(dev);
> pm_runtime_set_active(dev);
> @@ -309,6 +309,16 @@ static int ohci_platform_resume(struct device *dev)
>
> return 0;
> }
> +
> +static int ohci_platform_resume(struct device *dev)
> +{
> + return ohci_platform_resume_common(dev, false);
> +}
> +
> +static int ohci_platform_restore(struct device *dev)
> +{
> + return ohci_platform_resume_common(dev, true);
> +}
> #endif /* CONFIG_PM_SLEEP */
>
> static const struct of_device_id ohci_platform_ids[] = {
> @@ -325,8 +335,16 @@ static const struct platform_device_id ohci_platform_table[] = {
> };
> MODULE_DEVICE_TABLE(platform, ohci_platform_table);
>
> -static SIMPLE_DEV_PM_OPS(ohci_platform_pm_ops, ohci_platform_suspend,
> - ohci_platform_resume);
> +#ifdef CONFIG_PM_SLEEP
> +static const struct dev_pm_ops ohci_platform_pm_ops = {
> + .suspend = ohci_platform_suspend,
> + .resume = ohci_platform_resume,
> + .freeze = ohci_platform_suspend,
> + .thaw = ohci_platform_resume,
> + .poweroff = ohci_platform_suspend,
> + .restore = ohci_platform_restore,
> +};
> +#endif
>
> static struct platform_driver ohci_platform_driver = {
> .id_table = ohci_platform_table,
> @@ -335,7 +353,9 @@ static struct platform_driver ohci_platform_driver = {
> .shutdown = usb_hcd_platform_shutdown,
> .driver = {
> .name = "ohci-platform",
> +#ifdef CONFIG_PM_SLEEP
> .pm = &ohci_platform_pm_ops,
> +#endif
> .of_match_table = ohci_platform_ids,
> .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> }
> --
> 2.31.1
>
