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authorAlan Stern <stern@rowland.harvard.edu>2011-03-07 19:11:52 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2011-03-07 23:14:06 +0300
commit9b37596a2e860404503a3f2a6513db60c296bfdc (patch)
treef47f8e38895d0ce9db252328f686482bad79716f /drivers/usb/core/hcd-pci.c
parente4738e29bef8ed9bdd8a0606d0561557b4547649 (diff)
downloadlinux-9b37596a2e860404503a3f2a6513db60c296bfdc.tar.xz
USB: move usbcore away from hcd->state
The hcd->state variable is a disaster. It's not clearly owned by either usbcore or the host controller drivers, and they both change it from time to time, potentially stepping on each other's toes. It's not protected by any locks. And there's no mechanism to prevent it from going through an invalid transition. This patch (as1451) takes a first step toward fixing these problems. As it turns out, usbcore uses hcd->state for essentially only two things: checking whether the controller's root hub is running and checking whether the controller has died. Therefore the patch adds two new atomic bitflags to the hcd structure, to store these pieces of information. The new flags are used only by usbcore, and a private spinlock prevents invalid combinations (a dead controller's root hub cannot be running). The patch does not change the places where usbcore sets hcd->state, since HCDs may depend on them. Furthermore, there is one place in usb_hcd_irq() where usbcore still must use hcd->state: An HCD's interrupt handler can implicitly indicate that the controller died by setting hcd->state to HC_STATE_HALT. Nevertheless, the new code is a big improvement over the current code. The patch makes one other change. The hcd_bus_suspend() and hcd_bus_resume() routines now check first whether the host controller has died; if it has then they return immediately without calling the HCD's bus_suspend or bus_resume methods. This fixes the major problem reported in Bugzilla #29902: The system fails to suspend after a host controller dies during system resume. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Alex Terekhov <a.terekhov@gmail.com> CC: <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core/hcd-pci.c')
-rw-r--r--drivers/usb/core/hcd-pci.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index f71e8e307e0f..d37088591d9a 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -363,8 +363,7 @@ static int check_root_hub_suspended(struct device *dev)
struct pci_dev *pci_dev = to_pci_dev(dev);
struct usb_hcd *hcd = pci_get_drvdata(pci_dev);
- if (!(hcd->state == HC_STATE_SUSPENDED ||
- hcd->state == HC_STATE_HALT)) {
+ if (HCD_RH_RUNNING(hcd)) {
dev_warn(dev, "Root hub is not suspended\n");
return -EBUSY;
}
@@ -386,7 +385,7 @@ static int suspend_common(struct device *dev, bool do_wakeup)
if (retval)
return retval;
- if (hcd->driver->pci_suspend) {
+ if (hcd->driver->pci_suspend && !HCD_DEAD(hcd)) {
/* Optimization: Don't suspend if a root-hub wakeup is
* pending and it would cause the HCD to wake up anyway.
*/
@@ -427,7 +426,7 @@ static int resume_common(struct device *dev, int event)
struct usb_hcd *hcd = pci_get_drvdata(pci_dev);
int retval;
- if (hcd->state != HC_STATE_SUSPENDED) {
+ if (HCD_RH_RUNNING(hcd)) {
dev_dbg(dev, "can't resume, not suspended!\n");
return 0;
}
@@ -442,7 +441,7 @@ static int resume_common(struct device *dev, int event)
clear_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
- if (hcd->driver->pci_resume) {
+ if (hcd->driver->pci_resume && !HCD_DEAD(hcd)) {
if (event != PM_EVENT_AUTO_RESUME)
wait_for_companions(pci_dev, hcd);
@@ -475,10 +474,10 @@ static int hcd_pci_suspend_noirq(struct device *dev)
pci_save_state(pci_dev);
- /* If the root hub is HALTed rather than SUSPENDed,
+ /* If the root hub is dead rather than suspended,
* disallow remote wakeup.
*/
- if (hcd->state == HC_STATE_HALT)
+ if (HCD_DEAD(hcd))
device_set_wakeup_enable(dev, 0);
dev_dbg(dev, "wakeup: %d\n", device_may_wakeup(dev));