diff options
| author | David Brownell <david-b@pacbell.net> | 2007-11-28 14:50:03 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-12-14 10:31:55 -0800 |
| commit | 69a7da07962ffb3f0c3f20e9876b02838e7cf594 (patch) | |
| tree | bdd80f7b505e65a38096f13b6cc3f20ed18d95f5 | |
| parent | 97ce253a31e0208733fc8a3c40e09dea7308766c (diff) | |
| download | lwn-69a7da07962ffb3f0c3f20e9876b02838e7cf594.tar.gz lwn-69a7da07962ffb3f0c3f20e9876b02838e7cf594.zip | |
USB: fix up EHCI startup synchronization
patch 1cb52658b4f5b10a9e91f8e1c21ca2bcc1b9a3ca in mainline.
A recent patch added software synchronization during EHCI startup,
so ports aren't switched away from the companion controllers after
resets have started. This patch adds a short delay letting hardware
finish that port switching before any new resets begin ... so both
ends of that hardware race window are closed.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Dave Miller <davem@davemloft.net>
Cc: Dely Sy <dely.l.sy@intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 5caa8b35cca3..ba78f8e1584e 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -571,12 +571,15 @@ static int ehci_run (struct usb_hcd *hcd) * from the companions to the EHCI controller. If any of the * companions are in the middle of a port reset at the time, it * could cause trouble. Write-locking ehci_cf_port_reset_rwsem - * guarantees that no resets are in progress. + * guarantees that no resets are in progress. After we set CF, + * a short delay lets the hardware catch up; new resets shouldn't + * be started before the port switching actions could complete. */ down_write(&ehci_cf_port_reset_rwsem); hcd->state = HC_STATE_RUNNING; ehci_writel(ehci, FLAG_CF, &ehci->regs->configured_flag); ehci_readl(ehci, &ehci->regs->command); /* unblock posted writes */ + msleep(5); up_write(&ehci_cf_port_reset_rwsem); temp = HC_VERSION(ehci_readl(ehci, &ehci->caps->hc_capbase)); |