From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754498AbcKUNK0 (ORCPT ); Mon, 21 Nov 2016 08:10:26 -0500 Received: from mail-wm0-f47.google.com ([74.125.82.47]:37411 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754115AbcKUNKY (ORCPT ); Mon, 21 Nov 2016 08:10:24 -0500 Date: Mon, 21 Nov 2016 13:13:16 +0000 From: Lee Jones To: Andy Shevchenko Cc: linux-kernel@vger.kernel.org, Mika Westerberg Subject: Re: [PATCH v2 1/1] mfd: intel-lpss: Try to enable Memory-Write-Invalidate Message-ID: <20161121131316.GF3917@dell> References: <20161115103704.93476-1-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20161115103704.93476-1-andriy.shevchenko@linux.intel.com> User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 15 Nov 2016, Andy Shevchenko wrote: > Enable MWI mechanism if PCI bus master supports it. > > It might be potential benefit in some cases. Documentation [1] says that > standard Memory Write might supply more current data than in the CPU modified > cache line and "trashing a line in the cache may trash some data that is more > current that in the memory line". This allows to avoid potential retries and > other performance degradation issues on the bus. > > [1] PCI System Architecture, 4th edition, ISBN: 0-201-30974-2, pp.117-119. > > Signed-off-by: Andy Shevchenko > --- > In v2: > - extend commit message > drivers/mfd/intel-lpss-pci.c | 1 + > 1 file changed, 1 insertion(+) Applied, thanks. > diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c > index 50e78db..4756153 100644 > --- a/drivers/mfd/intel-lpss-pci.c > +++ b/drivers/mfd/intel-lpss-pci.c > @@ -41,6 +41,7 @@ static int intel_lpss_pci_probe(struct pci_dev *pdev, > > /* Probably it is enough to set this for iDMA capable devices only */ > pci_set_master(pdev); > + pci_try_set_mwi(pdev); > > ret = intel_lpss_probe(&pdev->dev, info); > if (ret) -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog