Daniel Glöckner a187b9c72d usb: musb: fix remote wakeup racing with suspend
[ Upstream commit ebc3dd688cd988754a304147753b13e58de1b5a1 ]

It has been observed that writing 0xF2 to the power register while it
reads as 0xF4 results in the register having the value 0xF0, i.e. clearing
RESUME and setting SUSPENDM in one go does not work. It might also violate
the USB spec to transition directly from resume to suspend, especially
when not taking T_DRSMDN into account. But this is what happens when a
remote wakeup occurs between SetPortFeature USB_PORT_FEAT_SUSPEND on the
root hub and musb_bus_suspend being called.

This commit returns -EBUSY when musb_bus_suspend is called while remote
wakeup is signalled and thus avoids to reset the RESUME bit. Ignoring
this error when musb_port_suspend is called from musb_hub_control is ok.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-21 04:02:59 +09:00
2018-06-21 04:02:49 +09:00
2018-06-21 04:02:59 +09:00
2018-06-16 09:45:18 +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.
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