This is a note to let you know that I've just added the patch titled
drm/msm/hdmi: Remove spurious IRQF_ONESHOT flag
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-msm-hdmi-remove-spurious-irqf_oneshot-flag.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8f46c2aaadb2bb9a7aead1c2d505ddd22167450f
Author: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Date: Tue Feb 1 17:47:33 2022 +0000
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@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>
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c
index e082e01b5e8d..0b756e84d393 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi.c
@@ -331,7 +331,7 @@ 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",
