8225bdaec5
[ Upstream commit 088604d37e23e9ec01a501d0e3630bc4f02027a0 ] Quoting the header comments, IRQF_ONESHOT is "Used by threaded interrupts which need to keep the irq line disabled until the threaded handler has been run.". When applied to an interrupt that doesn't request a threaded irq then IRQF_ONESHOT has a lesser known (undocumented?) side effect, which it to disable the forced threading of irqs. For "normal" kernels if there is no thread_fn then IRQF_ONESHOT is a nop. In this case disabling forced threading is not appropriate because the driver calls wake_up_all() (via msm_hdmi_i2c_irq) and also directly uses the regular spinlock API for locking (in msm_hdmi_hdcp_irq() ). Neither of these APIs can be called from no-thread interrupt handlers on PREEMPT_RT systems. Fix this by removing IRQF_ONESHOT. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Link: https://lore.kernel.org/r/20220201174734.196718-3-daniel.thompson@linaro.org Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Stable-dep-of: 152d394842bb ("drm/msm/hdmi: fix IRQ lifetime") Signed-off-by: Sasha Levin <sashal@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.