5ad7f18cd8
commit 4298388574da ("net: macb: restart tx after tx used bit read")
added support for restarting transmission. Restarting tx does not work
in case controller asserts TXUBR interrupt and TQBP is already at the end
of the tx queue. In that situation, restarting tx will immediately cause
assertion of another TXUBR interrupt. The driver will end up in an infinite
interrupt loop which it cannot break out of.
For cases where TQBP is at the end of the tx queue, instead
only clear TX_USED interrupt. As more data gets pushed to the queue,
transmission will resume.
This issue was observed on a Xilinx Zynq-7000 based board.
During stress test of the network interface,
driver would get stuck on interrupt loop within seconds or minutes
causing CPU to stall.
Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Tested-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220407161659.14532-1-tomas.melin@vaisala.com
Signed-off-by: Jakub Kicinski <kuba@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.
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.