On Thu, Oct 11, 2012 at 03:20:51PM -0400, Alan Stern wrote:
> On Thu, 11 Oct 2012, Peter Chen wrote:
>
>
> > > There is a port on the root hub with suspend status clear
> > > and enabled status set (which implies there must be a device
> > > attached to the port, because disconnected ports can't be
> > > enabled).
> > >
> > > Obviously if a port isn't enabled then it doesn't need any delay.
> > Is it ok to set one hcd flag, like hcd->unsuspended_device_on_port
> > to get condition at xxx_bus_suspend?
>
> Only if you're willing to change all the host controller drivers to
> make them set that flag!
Taking EHCI controller as an example, it just needs to change ehci_bus_resume,
if there is any enabled, unsuspended port, set hcd->unsuspended_device_on_port
>
> usb_bus_resume() can poll the port statuses to see if there are any
> enabled, unsuspended ports. If there aren't any, the delay can be
> skipped.
Taking EHCI controller as an example, you mean:
- Change hcd_bus_resume like below:
status = hcd->driver->bus_resume(hcd);
clear_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
if (status == 0) {
char buffer[6];
status = hcd->driver->hub_status_data(hcd, buffer);
if (status != 0) {
/* There are any enabled unsuspended ports */
/* TRSMRCY = 10 msec */
msleep(10);
spin_lock_irq(&hcd_root_hub_lock);
- Add get any enabled, unsuspended port as port change condition at
ehci_hub_status_data.
>
> How does that sound?
So, you prefer the latter one?
--
Best Regards,
Peter Chen
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