Pull Documentation fixes from Jonathan Corbet:
 "A handful of late-arriving fixes for the documentation tree"

* tag 'docs-5.7-2' of git://git.lwn.net/linux:
  Documentation: android: binderfs: add 'stats' mount option
  Documentation: driver-api/usb/writing_usb_driver.rst Updates documentation links
  docs: driver-api: address duplicate label warning
  Documentation: sysrq: fix RST formatting
  docs: kernel-parameters.txt: Fix broken references
  docs: kernel-parameters.txt: Remove nompx
  docs: filesystems: fix typo in qnx6.rst

In writing_usb_driver.rst:
Remove link to https://www.qbik.ch/usb/devices/ since it seems to be inactive since 2013
Update link to linux-usb mailing list archive

Signed-off-by: Joakim Lönnegren <joakimlonnegren@gmail.com>
Link: https://lore.kernel.org/r/20200312201354.285839-1-joakimlonnegren@gmail.om
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Using the generic notification chain is not reasonable with
the alternate modes because it would require dependencies
between the drivers of the components that need the
notifications, and the typec drivers.

There are no users for the alternate mode notifications, so
removing the chain and the API for it completely.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200211112531.86510-6-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert the PM documents to ReST, in order to allow them to
build with Sphinx.

The conversion is actually:
  - add blank lines and indentation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>

The syzkaller fuzzer reported a bug in the USB hub driver which turned
out to be caused by a negative runtime-PM usage counter.  This allowed
a hub to be runtime suspended at a time when the driver did not expect
it.  The symptom is a WARNING issued because the hub's status URB is
submitted while it is already active:

	URB 0000000031fb463e submitted while active
	WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363

The negative runtime-PM usage count was caused by an unfortunate
design decision made when runtime PM was first implemented for USB.
At that time, USB class drivers were allowed to unbind from their
interfaces without balancing the usage counter (i.e., leaving it with
a positive count).  The core code would take care of setting the
counter back to 0 before allowing another driver to bind to the
interface.

Later on when runtime PM was implemented for the entire kernel, the
opposite decision was made: Drivers were required to balance their
runtime-PM get and put calls.  In order to maintain backward
compatibility, however, the USB subsystem adapted to the new
implementation by keeping an independent usage counter for each
interface and using it to automatically adjust the normal usage
counter back to 0 whenever a driver was unbound.

This approach involves duplicating information, but what is worse, it
doesn't work properly in cases where a USB class driver delays
decrementing the usage counter until after the driver's disconnect()
routine has returned and the counter has been adjusted back to 0.
Doing so would cause the usage counter to become negative.  There's
even a warning about this in the USB power management documentation!

As it happens, this is exactly what the hub driver does.  The
kick_hub_wq() routine increments the runtime-PM usage counter, and the
corresponding decrement is carried out by hub_event() in the context
of the hub_wq work-queue thread.  This work routine may sometimes run
after the driver has been unbound from its interface, and when it does
it causes the usage counter to go negative.

It is not possible for hub_disconnect() to wait for a pending
hub_event() call to finish, because hub_disconnect() is called with
the device lock held and hub_event() acquires that lock.  The only
feasible fix is to reverse the original design decision: remove the
duplicate interface-specific usage counter and require USB drivers to
balance their runtime PM gets and puts.  As far as I know, all
existing drivers currently do this.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding the document to the usb index file and fixing a few
references. Also, exposing the code examples as "literal
blocks" so they are more easy to read.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Introducing a simple bus for the alternate modes. Bus allows
binding drivers to the discovered alternate modes the
partners support.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: changes for v4.18 merge window

A total of 98 non-merge commits, the biggest part being in dwc3 this
time around with a large refactoring of dwc3's transfer handling code.

We also have a new driver for Aspeed virtual hub controller.

Apart from that, just a list of miscellaneous fixes all over the place.

Now, this part of the code is duplicated and brings no extra value to
the driver. Let's remove it.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

It has no use anymore.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>