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由 Julia Cartwright 提交于
The MSM pinctrl driver currently implements an irq_chip for handling GPIO interrupts; due to how irq_chip handling is done, it's necessary for the irq_chip methods to be invoked from hardirq context, even on a a real-time kernel. Because the spinlock_t type becomes a "sleeping" spinlock w/ RT kernels, it is not suitable to be used with irq_chips. A quick audit of the operations under the lock reveal that they do only minimal, bounded work, and are therefore safe to do under a raw spinlock. On real-time kernels, this fixes an OOPs which looks like the following, as reported by Brian Wrenn: kernel BUG at kernel/locking/rtmutex.c:1014! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: spidev_irq(O) smsc75xx wcn36xx [last unloaded: spidev] CPU: 0 PID: 1163 Comm: irq/144-mmc0 Tainted: G W O 4.4.9-linaro-lt-qcom #1 PC is at rt_spin_lock_slowlock+0x80/0x2d8 LR is at rt_spin_lock_slowlock+0x68/0x2d8 [..] Call trace: rt_spin_lock_slowlock rt_spin_lock msm_gpio_irq_ack handle_edge_irq generic_handle_irq msm_gpio_irq_handler generic_handle_irq __handle_domain_irq gic_handle_irq Reported-by: NBrian Wrenn <dcbrianw@gmail.com> Tested-by: NBrian Wrenn <dcbrianw@gmail.com> Signed-off-by: NJulia Cartwright <julia@ni.com> Acked-by: NBjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
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