cbffaf7aa0
Essentially this patch moves the TX mailbox to position 63, regardless of timestamp based offloading or RX FIFO. So mainly the iflag register usage regarding TX has changed. The rest is consolidating RX FIFO and timestamp offloading as they now use both the same TX mailbox. The reason is a very annoying behavior regarding sending RTR frames when _not_ using RX FIFO: If a TX mailbox sent a RTR frame it becomes a RX mailbox. For that reason flexcan_irq disables the TX mailbox again. But if during the time the RTR was sent and the TX mailbox is disabled a new CAN frames is received, it is lost without notice. The reason is that so-called "Move-in" process starts from the lowest mailbox which happen to be a TX mailbox set to EMPTY. Steps to reproduce (I used an imx7d): 1. generate regular bursts of messages 2. send a RTR from flexcan with higher priority than burst messages every 1ms, e.g. cangen -I 0x100 -L 0 -g 1 -R can0 3. notice a lost message without notification after some seconds When running an iperf in parallel this problem is occurring even more frequently. Using filters is not possible as at least one single CAN-ID is allowed. Handling the TX MB during RX is also not possible as there is no race-free disable of RX MB. There is still a slight window when the described problem can occur. But for that all RX MB must be in use which is essentially next to an overrun. Still there will be no indication if it ever occurs. Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> |
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
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.