90d4fa39d0
It is incorrect to specify the no-ether-link property for the AVB device on
the Ebisu board. This is because the property should only be used when a
board does not provide a proper AVB_LINK signal. However, the Ebisu board
does provide this signal.
As per 87c059e9c39d ("arm64: dts: renesas: salvator-x: Remove renesas,
no-ether-link property") this fixes a bug:
Steps to reproduce:
- start AVB TX stream (Using aplay via MSE),
- disconnect+reconnect the eth cable,
- after a reconnection the eth connection goes iteratively up/down
without user interaction,
- this may heal after some seconds or even stay for minutes.
As the documentation specifies, the "renesas,no-ether-link" option
should be used when a board does not provide a proper AVB_LINK signal.
There is no need for this option enabled on RCAR H3/M3 Salvator-X/XS
and ULCB starter kits since the AVB_LINK is correctly handled by HW.
Choosing to keep or remove the "renesas,no-ether-link" option will have
impact on the code flow in the following ways:
- keeping this option enabled may lead to unexpected behavior since the
RX & TX are enabled/disabled directly from adjust_link function
without any HW interrogation,
- removing this option, the RX & TX will only be enabled/disabled after
HW interrogation. The HW check is made through the LMON pin in PSR
register which specifies AVB_LINK signal value (0 - at low level;
1 - at high level).
In conclusion, the present change is also a safety improvement because
it removes the "renesas,no-ether-link" option leading to a proper way
of detecting the link state based on HW interrogation and not on
software heuristic.
Fixes: 8441ef643d7d ("arm64: dts: renesas: r8a77990: ebisu: Enable EthernetAVB")
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[simon: updated changelog]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
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.
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.