drm/msm/hdmi: Remove spurious IRQF_ONESHOT flag

drm/msm/hdmi: Remove spurious IRQF_ONESHOT flag

[ 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>