From patchwork Wed Feb 5 11:26:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kai-Heng Feng X-Patchwork-Id: 11366161 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3E7C6112B for ; Wed, 5 Feb 2020 11:42:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2773621927 for ; Wed, 5 Feb 2020 11:42:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727355AbgBELmN (ORCPT ); Wed, 5 Feb 2020 06:42:13 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:54762 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727050AbgBELmM (ORCPT ); Wed, 5 Feb 2020 06:42:12 -0500 Received: from 61-220-137-37.hinet-ip.hinet.net ([61.220.137.37] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1izIpJ-0003Wg-4u; Wed, 05 Feb 2020 11:26:37 +0000 From: Kai-Heng Feng To: mathias.nyman@intel.com, gregkh@linuxfoundation.org, stern@rowland.harvard.edu Cc: acelan.kao@canonical.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Kai-Heng Feng Subject: [RESEND] [PATCH v2 1/3] xhci: Ensure link state is U3 after setting USB_SS_PORT_LS_U3 Date: Wed, 5 Feb 2020 19:26:31 +0800 Message-Id: <20200205112633.25995-1-kai.heng.feng@canonical.com> X-Mailer: git-send-email 2.17.1 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org The xHCI spec doesn't specify the upper bound of U3 transition time. For some devices 20ms is not enough, so we need to make sure the link state is in U3 before further actions. I've tried to use U3 Entry Capability by setting U3 Entry Enable in config register, however the port change event for U3 transition interrupts the system suspend process. For now let's use the less ideal method by polling PLS. Signed-off-by: Kai-Heng Feng --- v2: - Remove some redundant debug messages. - Use msleep loop outside if spinlock to stop pegging CPU. drivers/usb/host/xhci-hub.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 7a3a29e5e9d2..d3c5bcf76755 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1313,7 +1313,16 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, xhci_set_link_state(xhci, ports[wIndex], link_state); spin_unlock_irqrestore(&xhci->lock, flags); - msleep(20); /* wait device to enter */ + if (link_state == USB_SS_PORT_LS_U3) { + int retries = 10; + + while (retries--) { + msleep(10); /* wait device to enter */ + temp = readl(ports[wIndex]->addr); + if ((temp & PORT_PLS_MASK) == XDEV_U3) + break; + } + } spin_lock_irqsave(&xhci->lock, flags); temp = readl(ports[wIndex]->addr);