edd64f3079
The IPG clock is disabled at the end of imx_uart_shutdown(); we really don't want to run any IRQ handlers after this point. At least on i.MX8MN, the UART will happily continue to generate interrupts even with its clocks disabled, but in this state, all register writes are ignored (which will cause the shadow registers to differ from the actual register values, resulting in all kinds of weirdness). In a transfer without DMA, this could lead to the following sequence of events: - The UART finishes its transmission while imx_uart_shutdown() is run, triggering the TXDC interrupt (we can trigger this fairly reliably by writing a single byte to the TTY and closing it right away) - imx_uart_shutdown() finishes, disabling the UART clocks - imx_uart_int() -> imx_uart_transmit_buffer() -> imx_uart_stop_tx() imx_uart_stop_tx() should now clear UCR4_TCEN to disable the TXDC interrupt, but this register write is ineffective. This results in an interrupt storm. To disable all interrupts in the same place, and to avoid setting UCR4 twice, clearing UCR4_OREN is moved below del_timer_sync() as well; this should be harmless. Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com> Link: https://lore.kernel.org/r/20200925082412.12960-1-matthias.schiffer@ew.tq-group.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| 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.