drm/msm/hdmi: Remove spurious IRQF_ONESHOT flag

stable inclusion
from stable-v5.10.154
commit 8225bdaec5b043712e613ec6237842227e066695
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8225bdaec5b043712e613ec6237842227e066695



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[ Upstream commit 088604d3 ]

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: 152d3948 ("drm/msm/hdmi: fix IRQ lifetime")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lipeng Sang <sanglipeng1@jd.com>