Messages in this thread Patch in this message | | | Date | Wed, 12 Dec 2007 22:51:32 -0800 | From | Greg KH <> | Subject | [patch 11/60] USB: fix up EHCI startup synchronization |
| |
2.6.23-stable review patch. If anyone has any objections, please let us know.
------------------ From: David Brownell <david-b@pacbell.net>
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>
--- drivers/usb/host/ehci-hcd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -575,12 +575,15 @@ 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)); --
| |