From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-out.m-online.net ([212.18.0.10]:49667 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755310AbaGQIcE convert rfc822-to-8bit (ORCPT ); Thu, 17 Jul 2014 04:32:04 -0400 From: Marek Vasut To: "Uwe =?iso-8859-1?q?Kleine-K=F6nig?=" Subject: Re: [RFC] PCI: pci-imx6: Add delay to workaround kernel hang Date: Thu, 17 Jul 2014 10:23:10 +0200 Cc: Fabio Estevam , bhelgaas@google.com, r65037@freescale.com, shawn.guo@freescale.com, d.mueller@elsoft.ch, kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, tharvey@gateworks.com, Fabio Estevam References: <1403637507-9424-1-git-send-email-festevam@gmail.com> <20140717065148.GT11056@pengutronix.de> In-Reply-To: <20140717065148.GT11056@pengutronix.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Message-Id: <201407171023.10908.marex@denx.de> Sender: linux-pci-owner@vger.kernel.org List-ID: On Thursday, July 17, 2014 at 08:51:48 AM, Uwe Kleine-König wrote: > Hello, > > On Tue, Jun 24, 2014 at 04:18:27PM -0300, Fabio Estevam wrote: > > From: Fabio Estevam > > > > When the mx6 PCI conctroller is initialized in the bootloader we see a > > kernel hang inside imx6_add_pcie_port(). > > > > Adding a 30ms delay allows the kernel to boot. > > Just my thought on how to debug that: I'd try to bisect the pci init > routine in the boot loader. I.e. first only do the first half of the > initialisation in U-Boot. Depending on Linux being able to boot or not > initialize more or less on the next run. > > Maybe there is a single register write that makes Linux fail?! I am still hell-bent on thinking that the missing PCIe block reset is what makes the Linux fail. Missing block reset is always a problem. Or do we now have a mean to reset the PCIe block and it's PHY from software? Best regards, Marek Vasut