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Geert Uytterhoeven be92b3b5e5 Revert "ravb: Fixed to be able to unload modules" 
commit 77972b55fb upstream.

This reverts commit 1838d6c62f.

This commit moved the ravb_mdio_init() call (and thus the
of_mdiobus_register() call) from the ravb_probe() to the ravb_open()
call.  This causes a regression during system resume (s2idle/s2ram), as
new PHY devices cannot be bound while suspended.

During boot, the Micrel PHY is detected like this:

    Micrel KSZ9031 Gigabit PHY e6800000.ethernet-ffffffff:00: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=e6800000.ethernet-ffffffff:00, irq=228)
    ravb e6800000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

During system suspend, (A) defer_all_probes is set to true, and (B)
usermodehelper_disabled is set to UMH_DISABLED, to avoid drivers being
probed while suspended.

  A. If CONFIG_MODULES=n, phy_device_register() calling device_add()
     merely adds the device, but does not probe it yet, as
     really_probe() returns early due to defer_all_probes being set:

       dpm_resume+0x128/0x4f8
	 device_resume+0xcc/0x1b0
	   dpm_run_callback+0x74/0x340
	     ravb_resume+0x190/0x1b8
	       ravb_open+0x84/0x770
		 of_mdiobus_register+0x1e0/0x468
		   of_mdiobus_register_phy+0x1b8/0x250
		     of_mdiobus_phy_device_register+0x178/0x1e8
		       phy_device_register+0x114/0x1b8
			 device_add+0x3d4/0x798
			   bus_probe_device+0x98/0xa0
			     device_initial_probe+0x10/0x18
			       __device_attach+0xe4/0x140
				 bus_for_each_drv+0x64/0xc8
				   __device_attach_driver+0xb8/0xe0
				     driver_probe_device.part.11+0xc4/0xd8
				       really_probe+0x32c/0x3b8

     Later, phy_attach_direct() notices no PHY driver has been bound,
     and falls back to the Generic PHY, leading to degraded operation:

       Generic PHY e6800000.ethernet-ffffffff:00: attached PHY driver [Generic PHY] (mii_bus:phy_addr=e6800000.ethernet-ffffffff:00, irq=POLL)
       ravb e6800000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

  B. If CONFIG_MODULES=y, request_module() returns early with -EBUSY due
     to UMH_DISABLED, and MDIO initialization fails completely:

       mdio_bus e6800000.ethernet-ffffffff:00: error -16 loading PHY driver module for ID 0x00221622
       ravb e6800000.ethernet eth0: failed to initialize MDIO
       PM: dpm_run_callback(): ravb_resume+0x0/0x1b8 returns -16
       PM: Device e6800000.ethernet failed to resume: error -16

     Ignoring -EBUSY in phy_request_driver_module(), like was done for
     -ENOENT in commit 21e194425a ("net: phy: fix issue with loading
     PHY driver w/o initramfs"), would makes it fall back to the Generic
     PHY, like in the CONFIG_MODULES=n case.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable@vger.kernel.org
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-14 10:31:21 +02:00
arch mm: replace memmap_context by meminit_context 2020-10-07 08:00:08 +02:00
block block: ensure bdi->io_pages is always initialized 2020-09-12 13:40:22 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: af_alg - fix use-after-free in af_alg_accept() due to bh_lock_sock() 2020-07-09 09:37:10 +02:00
Documentation ata: make qc_prep return ata_completion_errors 2020-10-01 13:14:54 +02:00
drivers Revert "ravb: Fixed to be able to unload modules" 2020-10-14 10:31:21 +02:00
firmware Fix built-in early-load Intel microcode alignment 2020-01-23 08:21:29 +01:00
fs ep_create_wakeup_source(): dentry name can change under you... 2020-10-07 08:00:09 +02:00
include Fonts: Support FONT_EXTRA_WORDS macros for built-in fonts 2020-10-14 10:31:21 +02:00
init printk: queue wake_up_klogd irq_work only if per-CPU areas are ready 2020-07-22 09:32:13 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:18:40 +02:00
kernel ftrace: Move RCU is watching check after recursion check 2020-10-07 08:00:05 +02:00
lib Fonts: Support FONT_EXTRA_WORDS macros for built-in fonts 2020-10-14 10:31:21 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm: don't rely on system state to detect hot-plug operations 2020-10-07 08:00:08 +02:00
net netfilter: ctnetlink: add a range check for l3/l4 protonum 2020-10-07 08:00:09 +02:00
samples samples: bpf: Fix build error 2020-06-03 08:19:31 +02:00
scripts checkpatch: fix the usage of capture group ( ... ) 2020-09-09 19:04:32 +02:00
security selinux: sel_avc_get_stat_idx should increase position index 2020-10-01 13:14:33 +02:00
sound ALSA: asihpi: fix iounmap in error handler 2020-10-01 13:14:53 +02:00
tools objtool: Fix noreturn detection for ignored functions 2020-10-01 13:14:50 +02:00
usr initramfs: restore default compression behavior 2020-04-13 10:44:59 +02:00
virt KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:14:54 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-09-26 18:01:31 +02:00
Makefile Linux 4.19.150 2020-10-07 08:00:09 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

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.