Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755669AbbGaUT0 (ORCPT ); Fri, 31 Jul 2015 16:19:26 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:47731 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751167AbbGaUTU (ORCPT ); Fri, 31 Jul 2015 16:19:20 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kevin Strasser , Lu Baolu , Alan Stern Subject: [PATCH 4.1 111/267] usb: core: lpm: set lpm_capable for root hub device Date: Fri, 31 Jul 2015 12:39:22 -0700 Message-Id: <20150731194005.392249062@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150731194001.933895871@linuxfoundation.org> References: <20150731194001.933895871@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3094 Lines: 81 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lu Baolu commit 2d2a316765d956bc5cb6bb367b2ec52ca59ab8e9 upstream. Commit 25cd2882e2fc ("usb/xhci: Change how we indicate a host supports Link PM.") removed the code to set lpm_capable for USB 3.0 super-speed root hub. The intention of that change was to avoid touching usb core internal field, a.k.a. lpm_capable, and let usb core to set it by checking U1 and U2 exit latency values in the descriptor. Usb core checks and sets lpm_capable in hub_port_init(). Unfortunately, root hub is a special usb device as it has no parent. Hub_port_init() will never be called for a root hub device. That means lpm_capable will by no means be set for the root hub. As the result, lpm isn't functional at all in Linux kernel. This patch add the code to check and set lpm_capable when registering a root hub device. It could be back-ported to kernels as old as v3.15, that contains the Commit 25cd2882e2fc ("usb/xhci: Change how we indicate a host supports Link PM."). Reported-by: Kevin Strasser Signed-off-by: Lu Baolu Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hcd.c | 7 +++++-- drivers/usb/core/hub.c | 2 +- drivers/usb/core/usb.h | 1 + 3 files changed, 7 insertions(+), 3 deletions(-) --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1022,9 +1022,12 @@ static int register_root_hub(struct usb_ dev_name(&usb_dev->dev), retval); return (retval < 0) ? retval : -EMSGSIZE; } - if (usb_dev->speed == USB_SPEED_SUPER) { + + if (le16_to_cpu(usb_dev->descriptor.bcdUSB) >= 0x0201) { retval = usb_get_bos_descriptor(usb_dev); - if (retval < 0) { + if (!retval) { + usb_dev->lpm_capable = usb_device_supports_lpm(usb_dev); + } else if (usb_dev->speed == USB_SPEED_SUPER) { mutex_unlock(&usb_bus_list_lock); dev_dbg(parent_dev, "can't read %s bos descriptor %d\n", dev_name(&usb_dev->dev), retval); --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -122,7 +122,7 @@ struct usb_hub *usb_hub_to_struct_hub(st return usb_get_intfdata(hdev->actconfig->interface[0]); } -static int usb_device_supports_lpm(struct usb_device *udev) +int usb_device_supports_lpm(struct usb_device *udev) { /* USB 2.1 (and greater) devices indicate LPM support through * their USB 2.0 Extended Capabilities BOS descriptor. --- a/drivers/usb/core/usb.h +++ b/drivers/usb/core/usb.h @@ -65,6 +65,7 @@ extern int usb_hub_init(void); extern void usb_hub_cleanup(void); extern int usb_major_init(void); extern void usb_major_cleanup(void); +extern int usb_device_supports_lpm(struct usb_device *udev); #ifdef CONFIG_PM -- 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/