Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933242Ab0GAVRw (ORCPT ); Thu, 1 Jul 2010 17:17:52 -0400 Received: from kroah.org ([198.145.64.141]:33087 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932727Ab0GAVO4 (ORCPT ); Thu, 1 Jul 2010 17:14:56 -0400 X-Mailbox-Line: From gregkh@clark.site Thu Jul 1 10:42:59 2010 Message-Id: <20100701174259.575723595@clark.site> User-Agent: quilt/0.48-10.1 Date: Thu, 01 Jul 2010 10:44:05 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Sarah Sharp Subject: [155/200] USB: xhci: Wait for controller to be ready after reset. In-Reply-To: <20100701175201.GA2149@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1849 Lines: 56 2.6.34-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sarah Sharp commit 2d62f3eea98354d61f90d6b115eecf9be5f4bdfe upstream. After software resets an xHCI host controller, it must wait for the "Controller Not Ready" (CNR) bit in the status register to be cleared. Software is not supposed to ring any doorbells or write to any registers except the status register until this bit is cleared. Signed-off-by: Sarah Sharp Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -142,6 +142,7 @@ int xhci_reset(struct xhci_hcd *xhci) { u32 command; u32 state; + int ret; state = xhci_readl(xhci, &xhci->op_regs->status); if ((state & STS_HALT) == 0) { @@ -156,7 +157,17 @@ int xhci_reset(struct xhci_hcd *xhci) /* XXX: Why does EHCI set this here? Shouldn't other code do this? */ xhci_to_hcd(xhci)->state = HC_STATE_HALT; - return handshake(xhci, &xhci->op_regs->command, CMD_RESET, 0, 250 * 1000); + ret = handshake(xhci, &xhci->op_regs->command, + CMD_RESET, 0, 250 * 1000); + if (ret) + return ret; + + xhci_dbg(xhci, "Wait for controller to be ready for doorbell rings\n"); + /* + * xHCI cannot write to any doorbells or operational registers other + * than status until the "Controller Not Ready" flag is cleared. + */ + return handshake(xhci, &xhci->op_regs->status, STS_CNR, 0, 250 * 1000); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/