Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753720AbaFXNY6 (ORCPT ); Tue, 24 Jun 2014 09:24:58 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59600 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753641AbaFXNY4 (ORCPT ); Tue, 24 Jun 2014 09:24:56 -0400 Date: Tue, 24 Jun 2014 09:24:44 -0400 From: Greg Kroah-Hartman To: "Chen, Alvin" Cc: Alan Stern , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Boon Leong Ong Subject: Re: [PATCH] USB: ehci-pci: USB host controller support for Intel Quark X1000 Message-ID: <20140624132444.GA1215@kroah.com> References: <1403625103-28078-1-git-send-email-alvin.chen@intel.com> <1403625103-28078-2-git-send-email-alvin.chen@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1403625103-28078-2-git-send-email-alvin.chen@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 24, 2014 at 08:51:43AM -0700, Chen, Alvin wrote: > From: Bryan O'Donoghue > > This patch is to enable USB host controller for Intel Quark X1000. Add pci quirks > to adjust the packet buffer in/out threshold value, and ensure EHCI packet buffer > i/o threshold value is reconfigured to half. > > Signed-off-by: Bryan O'Donoghue > Signed-off-by: Alvin (Weike) Chen > --- > drivers/usb/host/ehci-pci.c | 4 ++++ > drivers/usb/host/pci-quirks.c | 42 +++++++++++++++++++++++++++++++++++++++++ > drivers/usb/host/pci-quirks.h | 2 ++ > 3 files changed, 48 insertions(+) > > diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c > index 3e86bf4..33cfa23 100644 > --- a/drivers/usb/host/ehci-pci.c > +++ b/drivers/usb/host/ehci-pci.c > @@ -50,6 +50,10 @@ static int ehci_pci_reinit(struct ehci_hcd *ehci, struct pci_dev *pdev) > if (!retval) > ehci_dbg(ehci, "MWI active\n"); > > + /* Reset the threshold limit */ > + if(unlikely(usb_is_intel_qrk(pdev))) Why unlikely()? Have you measured a speed difference here? And this is a _very_ slow path, what does that speed difference you measured help with? thanks, greg k-h -- 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/