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[ Upstream commit 23b5f73266 ]
During HARD_RESET the data link is disconnected.
For self powered device, the spec is advising against doing that.
>From USB_PD_R3_0
7.1.5 Response to Hard Resets
Device operation during and after a Hard Reset is defined as follows:
Self-powered devices Should Not disconnect from USB during a Hard Reset
(see Section 9.1.2).
Bus powered devices will disconnect from USB during a Hard Reset due to the
loss of their power source.
Tackle this by letting TCPM know whether the device is self or bus powered.
This overcomes unnecessary port disconnections from hard reset.
Also, speeds up the enumeration time when connected to Type-A ports.
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---------
Version history:
V3:
Rebase on top of usb-next
V2:
Based on feedback from heikki.krogerus@linux.intel.com
- self_powered added to the struct tcpm_port which is populated from
a. "connector" node of the device tree in tcpm_fw_get_caps()
b. "self_powered" node of the tcpc_config in tcpm_copy_caps
Based on feedbase from linux@roeck-us.net
- Code was refactored
- SRC_HARD_RESET_VBUS_OFF sets the link state to false based
on self_powered flag
V1 located here:
https://lkml.org/lkml/2018/9/13/94
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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.