Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753870AbbFIXvB (ORCPT ); Tue, 9 Jun 2015 19:51:01 -0400 Received: from na3sys010aog111.obsmtp.com ([74.125.245.90]:40779 "EHLO mail-la0-f44.google.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751380AbbFIXuy (ORCPT ); Tue, 9 Jun 2015 19:50:54 -0400 X-Greylist: delayed 392 seconds by postgrey-1.27 at vger.kernel.org; Tue, 09 Jun 2015 19:50:53 EDT MIME-Version: 1.0 From: Roland Dreier Date: Tue, 9 Jun 2015 16:43:59 -0700 Message-ID: Subject: Regression in 3.10.80 vs. 3.10.79 To: LKML , "Rafael J. Wysocki" , George McCollister Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2000 Lines: 50 Hi, I recently updated from 3.10.79 to 3.10.80, and my system wouldn't boot any more. I tracked this down to commit 92c934b10ec3 ("ACPI / init: Fix the ordering of acpi_reserve_resources()"). With that commit reverted, my system is OK again. What happens is that ahci fails to initialize because pcim_iomap_regions_request_all() fails with EBUSY, due to a resource conflict on the first IO region of the ahci device. Since my root device is on ahci, that's the end of that. I'm sure this is due to a BIOS / ACPI table bug on my particular platform, but that's scant comfort when the system won't boot :) I patched 3.10.80 so that ahci continues to initialize after the EBUSY, and relevant parts of the kernel log seem to be: [ 3.836643,26] system 00:06: [io 0x0400-0x047f] could not be reserved ... [ 3.844112,26] pci 0000:00:1f.2: BAR 0: assigned [io 0x0410-0x0417] ... [ 6.020040,00] ahci 0000:00:1f.2: BAR 0: can't reserve [io 0x0410-0x0417] and /proc/ioports shows 0410-0415 : ACPI CPU throttle So if I'm understanding properly, for some reason we discover but fail to reserve the region with the ACPI resources, then PCI decides to assign ahci IO ports into that range, then ACPI loads and reserves 0x0410-0x0415, and then ahci fails to load. If I fully revert the patch, then I see [ 3.853857,08] system 00:06: [io 0x0400-0x047f] has been reserved ... [ 3.861806,08] pci 0000:00:1f.2: BAR 0: assigned [io 0x0820-0x0827] We're able to reserve the range, and then PCI assigns ahci into a non-conflicting range. I understand that the change here fixed another regression, but I'm wondering if there's a way to make everyone happy here? I can provide debugging info from my system as required... Thanks, Roland -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/