Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752839AbcLGA3y (ORCPT ); Tue, 6 Dec 2016 19:29:54 -0500 Received: from mail-pg0-f52.google.com ([74.125.83.52]:36800 "EHLO mail-pg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751572AbcLGA3x (ORCPT ); Tue, 6 Dec 2016 19:29:53 -0500 From: Jon Mason To: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC] PCI: Change default MPS behavior Date: Tue, 6 Dec 2016 19:20:27 -0500 Message-Id: <1481070027-9096-1-git-send-email-jon.mason@broadcom.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1149 Lines: 28 Not all systems have a BIOS or firmware to preconfigure the PCIE MPS prior to Linux booting. Without any firmware to pre-setup the MPS, the PCIE_BUS_DEFAULT will simply set everything to 0 (128b). This behavior causes these systems to have non-optimal MPS values. To get around this issue, change the default value of pcie_bus_config to be PCIE_BUS_SAFE. This configures all systems to use better values for the MPS, at the expense of any potential HW errata that might not like being changed. Signed-off-by: Jon Mason --- drivers/pci/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index ba34907..94d574e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -88,7 +88,7 @@ unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE; #define DEFAULT_HOTPLUG_BUS_SIZE 1 unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE; -enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT; +enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_SAFE; /* * The default CLS is used if arch didn't set CLS explicitly and not -- 2.7.4