From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Subject: Re: Legacy features in PCI Express devices Date: Mon, 13 Mar 2017 04:08:03 -0700 Message-ID: <1489403283.21692.1.camel@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: linux-pci , Bjorn Helgaas , David Laight , Robin Murphy , Thibaud Cornic , Phuong Nguyen , Linux ARM , netdev , Tim Harvey , Arnd Bergmann To: Mason Return-path: Received: from mail-pg0-f66.google.com ([74.125.83.66]:34582 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752799AbdCMRHC (ORCPT ); Mon, 13 Mar 2017 13:07:02 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2017-03-13 at 17:10 +0100, Mason wrote: > Hello, > > There are two revisions of our PCI Express controller. > > Rev 1 did not support the following features: > > 1) legacy PCI interrupt delivery (INTx signals) I'm not sure about this... > 2) I/O address space But yes, definitely some support this. We're working on a new type of network controller that uses I/O for some types of low latency feature support. - Greg > > Internally, someone stated that such missing support would prevent > some PCIe cards from working with our controller. > > Are there really modern PCIe cards that require 1) and/or 2) > to function? > > Can someone provide examples of such cards, so that I may test them > on both revisions? > > I was told to check ath9k-based cards. Any other examples? > > Looking around, I came across this thread: > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/418254.html > "i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity" > > IIUC, although some PCIe boards do support MSI, the driver might not > put in the work to use that infrastructure, and instead reverts to > legacy interrupts. (So it is a SW issue, in a sense.) > > Regards. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Message-ID: <1489403283.21692.1.camel@gmail.com> Subject: Re: Legacy features in PCI Express devices From: Greg To: Mason Cc: linux-pci , Bjorn Helgaas , David Laight , Robin Murphy , Thibaud Cornic , Phuong Nguyen , Linux ARM , netdev , Tim Harvey , Arnd Bergmann Date: Mon, 13 Mar 2017 04:08:03 -0700 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-ID: On Mon, 2017-03-13 at 17:10 +0100, Mason wrote: > Hello, > > There are two revisions of our PCI Express controller. > > Rev 1 did not support the following features: > > 1) legacy PCI interrupt delivery (INTx signals) I'm not sure about this... > 2) I/O address space But yes, definitely some support this. We're working on a new type of network controller that uses I/O for some types of low latency feature support. - Greg > > Internally, someone stated that such missing support would prevent > some PCIe cards from working with our controller. > > Are there really modern PCIe cards that require 1) and/or 2) > to function? > > Can someone provide examples of such cards, so that I may test them > on both revisions? > > I was told to check ath9k-based cards. Any other examples? > > Looking around, I came across this thread: > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/418254.html > "i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity" > > IIUC, although some PCIe boards do support MSI, the driver might not > put in the work to use that infrastructure, and instead reverts to > legacy interrupts. (So it is a SW issue, in a sense.) > > Regards. From mboxrd@z Thu Jan 1 00:00:00 1970 From: gvrose8192@gmail.com (Greg) Date: Mon, 13 Mar 2017 04:08:03 -0700 Subject: Legacy features in PCI Express devices In-Reply-To: References: Message-ID: <1489403283.21692.1.camel@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 2017-03-13 at 17:10 +0100, Mason wrote: > Hello, > > There are two revisions of our PCI Express controller. > > Rev 1 did not support the following features: > > 1) legacy PCI interrupt delivery (INTx signals) I'm not sure about this... > 2) I/O address space But yes, definitely some support this. We're working on a new type of network controller that uses I/O for some types of low latency feature support. - Greg > > Internally, someone stated that such missing support would prevent > some PCIe cards from working with our controller. > > Are there really modern PCIe cards that require 1) and/or 2) > to function? > > Can someone provide examples of such cards, so that I may test them > on both revisions? > > I was told to check ath9k-based cards. Any other examples? > > Looking around, I came across this thread: > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/418254.html > "i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity" > > IIUC, although some PCIe boards do support MSI, the driver might not > put in the work to use that infrastructure, and instead reverts to > legacy interrupts. (So it is a SW issue, in a sense.) > > Regards.