From 5340ba827b6269ccd2dcfd3d966626d9dd75d5d4 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 10 Jun 2008 14:59:43 -0400 Subject: [PATCH] USB: don't use reset-resume if drivers don't support it This patch tries to identify which devices are able to accept reset-resume handling, by checking that there is at least one interface driver bound and that all of the drivers have a reset_resume method defined. If these conditions don't hold then during resume processing, the device is logicall disconnected. This is only a temporary fix. Later on we will explicitly unbind drivers that can't handle reset-resumes. Signed-off-by: Linus Torvalds Signed-off-by: Alan Stern Cc: Oliver Neukum Cc: Pavel Machek Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 46 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 44 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 8eb4da332f5..94789be54ca 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -644,6 +644,48 @@ static void hub_stop(struct usb_hub *hub) #ifdef CONFIG_PM +/* Try to identify which devices need USB-PERSIST handling */ +static int persistent_device(struct usb_device *udev) +{ + int i; + int retval; + struct usb_host_config *actconfig; + + /* Explicitly not marked persistent? */ + if (!udev->persist_enabled) + return 0; + + /* No active config? */ + actconfig = udev->actconfig; + if (!actconfig) + return 0; + + /* FIXME! We should check whether it's open here or not! */ + + /* + * Check that all the interface drivers have a + * 'reset_resume' entrypoint + */ + retval = 0; + for (i = 0; i < actconfig->desc.bNumInterfaces; i++) { + struct usb_interface *intf; + struct usb_driver *driver; + + intf = actconfig->interface[i]; + if (!intf->dev.driver) + continue; + driver = to_usb_driver(intf->dev.driver); + if (!driver->reset_resume) + return 0; + /* + * We have at least one driver, and that one + * has a reset_resume method. + */ + retval = 1; + } + return retval; +} + static void hub_restart(struct usb_hub *hub, int type) { struct usb_device *hdev = hub->hdev; @@ -689,8 +731,8 @@ static void hub_restart(struct usb_hub *hub, int type) * turn off the various status changes to prevent * khubd from disconnecting it later. */ - if (udev->persist_enabled && status == 0 && - !(portstatus & USB_PORT_STAT_ENABLE)) { + if (status == 0 && !(portstatus & USB_PORT_STAT_ENABLE) && + persistent_device(udev)) { if (portchange & USB_PORT_STAT_C_ENABLE) clear_port_feature(hub->hdev, port1, USB_PORT_FEAT_C_ENABLE); -- 2.20.1