From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:60927 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752504AbaGQGwE (ORCPT ); Thu, 17 Jul 2014 02:52:04 -0400 Date: Thu, 17 Jul 2014 08:51:48 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Fabio Estevam Cc: bhelgaas@google.com, r65037@freescale.com, shawn.guo@freescale.com, marex@denx.de, d.mueller@elsoft.ch, kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, tharvey@gateworks.com, Fabio Estevam Subject: Re: [RFC] PCI: pci-imx6: Add delay to workaround kernel hang Message-ID: <20140717065148.GT11056@pengutronix.de> References: <1403637507-9424-1-git-send-email-festevam@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <1403637507-9424-1-git-send-email-festevam@gmail.com> Sender: linux-pci-owner@vger.kernel.org List-ID: 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?! Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |