From: David Brownell Date: Wed, 14 Nov 2007 00:22:30 +0000 (-0800) Subject: USB: fix up EHCI startup synchronization X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1cb52658b4f5b10a9e91f8e1c21ca2bcc1b9a3ca;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git USB: fix up EHCI startup synchronization 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 Cc: Dave Miller Cc: Dely Sy Cc: stable Cc: Alan Stern Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index c1514442883e..5f2d74ed5ad7 100644 --- 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));