From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59366 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752718AbcFFOqC (ORCPT ); Mon, 6 Jun 2016 10:46:02 -0400 Date: Mon, 6 Jun 2016 07:46:00 -0700 From: "gregkh@linuxfoundation.org" To: "Koehrer Mathias (ETAS/ESW5)" Cc: "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "bhelgaas@google.com" , "hjk@hansjkoch.de" Subject: Re: [PATCH] Introducing kernel option to force all PCI memory resources to be page aligned. Fixes issues with uio based drivers. Message-ID: <20160606144600.GA6126@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-pci-owner@vger.kernel.org List-ID: On Mon, Jun 06, 2016 at 06:53:28AM +0000, Koehrer Mathias (ETAS/ESW5) wrote: > Some uio based PCI drivers (e.g. uio_cif) do not work if the assigned > PCI memory resources are not page aligned. > By using the kernel option "pci=resource_alignment" it is possible to force > single PCI boards to use page alignment for their memory resources. > However, this is fairly cumbersome if multiple of these cards are in use. > This patch adds another kernel option "pci=resources_page_aligned" > that allows to set the default alignment of PCI memory resources to > be page aligned. > Overwriting of this default alignment via "pci=resource_alignment" is > still possible. This seems like a very large hammer for a very specific problem with a card that seems to be not-in-spec (I can't find anywhere that requires resources to be "page" aligned in the PCI spec). Why not fix the firmware in these cards? thanks, greg k-h