On Fri, 8 Oct 2010, Sarah Sharp wrote:
> I've done some more testing, and Andiry's seven PM patches (mostly)
> work, when I apply the two extra patches that are attached. The first
> patch fixes the control endpoint issue I described, and the second patch
> fixes an issue with persistent USB 3.0 devices across suspend with a
> power loss and hibernate.
>
> Alan, could you look over the second patch? It fixes the issue I was
> seeing, but I'm not sure if there are further-reaching implications for
> khubd when a USB 3.0 port is not disabled after a hub reset-resume.
It looks okay to me. Telling usbcore that a SuperSpeed port isn't
enabled when it really is shouldn't cause too many problems. This
happens anyway when a device is first plugged in.
> The quick fix is to pretend the port is disabled in hub_activate(), by
> clearing the local variable. But I'm not sure what other parts of the hub
> driver need to be changed because they have assumptions about when ports
> will be disabled.
>
> Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/core/hub.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 6035fe3..b5f46fb 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -758,6 +758,9 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
> clear_port_feature(hdev, port1,
> USB_PORT_FEAT_ENABLE);
> portstatus &= ~USB_PORT_STAT_ENABLE;
> + } else {
> + /* Pretend that power was lost for USB3 devs */
> + portstatus &= ~USB_PORT_STAT_ENABLE;
> }
Instead of duplicating the assignment to portstatus, you could move the
existing assignment outside the "if" statement. That would reflect
what's really going on -- you're telling the hub driver that the port
is disabled, even though you can't actually disable a SuperSpeed port.
Alan Stern
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