On Wed, Aug 31, 2022 at 12:59:10PM +0800, Yinbo Zhu wrote:
> 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 v2:
> 1. Revise the commit log infomation.
> 2. Wrap the ohci_platform_renew() function with two
> helpers that are ohci_platform_renew_hibernated()
> and ohci_platform_renew().
>
> drivers/usb/host/ohci-platform.c | 49 ++++++++++++++++++++++++++++++--
> 1 file changed, 46 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/host/ohci-platform.c b/drivers/usb/host/ohci-platform.c
> index 0adae6265127..56cb424d3bb0 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_renew(struct device *dev)
> {
> struct usb_hcd *hcd = dev_get_drvdata(dev);
> struct usb_ohci_pdata *pdata = dev_get_platdata(dev);
> @@ -297,6 +297,7 @@ static int ohci_platform_resume(struct device *dev)
>
> if (pdata->power_on) {
> int err = pdata->power_on(pdev);
> +
> if (err < 0)
> return err;
> }
> @@ -309,6 +310,38 @@ static int ohci_platform_resume(struct device *dev)
>
> return 0;
> }
> +
> +static int ohci_platform_renew_hibernated(struct device *dev)
> +{
> + struct usb_hcd *hcd = dev_get_drvdata(dev);
> + struct usb_ohci_pdata *pdata = dev_get_platdata(dev);
> + struct platform_device *pdev = to_platform_device(dev);
> +
> + if (pdata->power_on) {
> + int err = pdata->power_on(pdev);
> +
> + if (err < 0)
> + return err;
> + }
> +
> + ohci_resume(hcd, true);
> +
> + pm_runtime_disable(dev);
> + pm_runtime_set_active(dev);
> + pm_runtime_enable(dev);
> +
> + return 0;
> +}
> +
> +static int ohci_platform_resume(struct device *dev)
> +{
> + return ohci_platform_renew(dev);
> +}
> +
> +static int ohci_platform_restore(struct device *dev)
> +{
> + return ohci_platform_renew_hibernated(dev);
> +}
I really do not see any point in these helper routines. Why not just
use these names (ohci_platform_resume and ohci_platform_restore) for the
actual routines and forget about the _renew names?
Although if it were me, I'd do it more like this:
static int ohci_platform_resume_common(struct device *dev, bool hibernated)
{ ... }
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);
}
Alan Stern
