mirror of https://gitee.com/openkylin/linux.git
3c7b30f704
The BCM2835 pinctrl driver acquires a spinlock in its ->irq_enable, ->irq_disable and ->irq_set_type callbacks. Spinlocks become sleeping locks with CONFIG_PREEMPT_RT_FULL=y, therefore invocation of one of the callbacks in atomic context may cause a hard lockup if at least two GPIO pins in the same bank are used as interrupts. The issue doesn't occur with just a single interrupt pin per bank because the lock is never contended. I'm experiencing such lockups with GPIO 8 and 28 used as level-triggered interrupts, i.e. with ->irq_disable being invoked on reception of every IRQ. The critical section protected by the spinlock is very small (one bitop and one RMW of an MMIO register), hence converting to a raw spinlock seems a better trade-off than converting the driver to threaded IRQ handling (which would increase latency to handle an interrupt). Cc: Mathias Duckeck <m.duckeck@kunbus.de> Signed-off-by: Lukas Wunner <lukas@wunner.de> Acked-by: Julia Cartwright <julia@ni.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> |
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| arch | ||
| block | ||
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| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
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| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
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| Kbuild | ||
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| 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.