From: Daniel Thompson <daniel.thompson@xxxxxxxxxx> [ 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@xxxxxxxxxx> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220201174734.196718-3-daniel.thompson@xxxxxxxxxx Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> Stable-dep-of: 152d394842bb ("drm/msm/hdmi: fix IRQ lifetime") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/msm/hdmi/hdmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c index 47796e12b432..28823fd94f9f 100644 --- a/drivers/gpu/drm/msm/hdmi/hdmi.c +++ b/drivers/gpu/drm/msm/hdmi/hdmi.c @@ -327,7 +327,7 @@ int msm_hdmi_modeset_init(struct hdmi *hdmi, } ret = devm_request_irq(&pdev->dev, hdmi->irq, - msm_hdmi_irq, IRQF_TRIGGER_HIGH | IRQF_ONESHOT, + msm_hdmi_irq, IRQF_TRIGGER_HIGH, "hdmi_isr", hdmi); if (ret < 0) { DRM_DEV_ERROR(dev->dev, "failed to request IRQ%u: %d\n", -- 2.35.1
