b1275cdd74
When I tried to fix the watchdog of rt2800, I found that sometimes the watchdog can not reset the hung device. This is because the queue is not completely stuck, it just becomes very slow. The MTK vendor driver for the new chip MT7603/MT7612 has a DMA busy watchdog to detect device hangs by checking DMA busy status. This watchdog implementation is something similar to it. To reduce unnecessary reset, we can check the INT_SOURCE_CSR register together as I found that when the radio hung, the RX/TX coherent interrupt will always stuck at triggered state. The 'watchdog' module parameter has been extended to control all watchdogs(0=disabled, 1=hang watchdog, 2=DMA watchdog, 3=both). This new watchdog function is a slight schedule and it won't affect the transmission speed. So we can turn on it by default. Due to the INT_SOURCE_CSR register is invalid on rt2800 USB NICs, the DMA busy watchdog will be automatically disabled for them. Tested on MT7620 and RT5350. Signed-off-by: Shiji Yang <yangshiji66@outlook.com> Acked-by: Stanislaw Gruszka <stf_xl@wp.pl> Signed-off-by: Kalle Valo <kvalo@kernel.org> Link: https://lore.kernel.org/r/TYAP286MB0315D7462CE08A119A99DE34BCA4A@TYAP286MB0315.JPNP286.PROD.OUTLOOK.COM
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.