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Koen Vandeputte 91e019af29 PCI: dwc: Fix enumeration end when reaching root subordinate
commit fc110ebdd0 upstream.

The subordinate value indicates the highest bus number which can be
reached downstream though a certain device.

Commit a20c7f36bd ("PCI: Do not allocate more buses than available in
parent") ensures that downstream devices cannot assign busnumbers higher
than the upstream device subordinate number, which was indeed illogical.

By default, dw_pcie_setup_rc() inits the Root Complex subordinate to a
value of 0x01.

Due to this combined with above commit, enumeration stops digging deeper
downstream as soon as bus num 0x01 has been assigned, which is always the
case for a bridge device.

This results in all devices behind a bridge bus remaining undetected, as
these would be connected to bus 0x02 or higher.

Fix this by initializing the RC to a subordinate value of 0xff, which is
not altering hardware behaviour in any way, but informs probing function
pci_scan_bridge() later on which reads this value back from register.

The following nasty errors during boot are also fixed by this:

  pci_bus 0000:02: busn_res: can not insert [bus 02-ff] under [bus 01] (conflicts with (null) [bus 01])
  ...
  pci_bus 0000:03: [bus 03] partially hidden behind bridge 0000:01 [bus 01]
  ...
  pci_bus 0000:04: [bus 04] partially hidden behind bridge 0000:01 [bus 01]
  ...
  pci_bus 0000:05: [bus 05] partially hidden behind bridge 0000:01 [bus 01]
  pci_bus 0000:02: busn_res: [bus 02-ff] end is updated to 05
  pci_bus 0000:02: busn_res: can not insert [bus 02-05] under [bus 01] (conflicts with (null) [bus 01])
  pci_bus 0000:02: [bus 02-05] partially hidden behind bridge 0000:01 [bus 01]

Fixes: a20c7f36bd ("PCI: Do not allocate more buses than available in
parent")
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Cc: stable@vger.kernel.org	# v4.15+
Cc: Binghui Wang <wangbinghui@hisilicon.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jianguo Sun <sunjianguo1@huawei.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Minghuan Lian <minghuan.Lian@freescale.com>
Cc: Mingkai Hu <mingkai.hu@freescale.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Pratyush Anand <pratyush.anand@gmail.com>
Cc: Richard Zhu <hongxing.zhu@nxp.com>
Cc: Roy Zang <tie-fei.zang@freescale.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Stanimir Varbanov <svarbanov@mm-sol.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Xiaowei Song <songxiaowei@hisilicon.com>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-03-15 10:54:32 +01:00
arch MIPS: OCTEON: irq: Check for null return on kzalloc allocation 2018-03-15 10:54:32 +01:00
block blk-mq: don't call io sched's .requeue_request when requeueing rq to ->dispatch 2018-03-08 22:41:20 -08:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: af_alg - Fix race around ctx->rcvused by making it atomic_t 2018-03-03 10:24:29 +01:00
Documentation KVM: x86: fix backward migration with async_PF 2018-03-11 16:23:23 +01:00
drivers PCI: dwc: Fix enumeration end when reaching root subordinate 2018-03-15 10:54:32 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs NFS: Fix unstable write completion 2018-03-15 10:54:27 +01:00
include drm/nouveau: prefer XBGR2101010 for addfb ioctl 2018-03-15 10:54:30 +01:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel workqueue: Allow retrieval of current task's work struct 2018-03-15 10:54:29 +01:00
lib lib/mpi: Fix umul_ppmm() for MIPS64r6 2018-03-03 10:24:29 +01:00
mm mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()' 2018-03-03 10:24:21 +01:00
net net/smc: fix NULL pointer dereference on sock_create_kern() error path 2018-03-15 10:54:28 +01:00
samples samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1 2017-12-20 10:10:31 +01:00
scripts scripts/kernel-doc: Don't fail with status != 0 if error encountered with -none 2018-02-25 11:07:58 +01:00
security selinux: skip bounded transition processing if the policy isn't loaded 2018-02-25 11:07:49 +01:00
sound ASoC: Intel: kbl: fix jack name 2018-03-15 10:54:23 +01:00
tools bpf: allow xadd only on aligned memory 2018-03-11 16:23:22 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: mmu: Fix overlap between public and private memslots 2018-03-08 22:41:24 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS kmemcheck: rip it out 2018-02-22 15:42:24 +01:00
Makefile kbuild: move "_all" target out of $(KBUILD_SRC) conditional 2018-03-15 10:54:21 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.