The threaded IRQ is requested without IRQF_ONESHOT, allowing hardirq to preempt the threaded handler. This creates a read-modify-write race on HPD interrupt mask registers between the hardirq mute and thread unmute operations.
Add IRQF_ONESHOT to keep the IRQ line masked during thread execution, which eliminates the race and makes the per-event mute/unmute calls in hardirq and thread handlers redundant. Move interrupt status clearing to the beginning of the threaded handler, before drm_helper_hpd_irq_event(), to avoid losing events that arrive during the event handling. Signed-off-by: Damon Ding <[email protected]> --- .../gpu/drm/bridge/analogix/analogix_dp_core.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index 7ef8ef812b55..4fe248e66515 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -707,10 +707,8 @@ static irqreturn_t analogix_dp_hardirq(int irq, void *arg) u32 irq_type; irq_type = analogix_dp_get_irq_type(dp); - if (irq_type) { - analogix_dp_mute_hpd_interrupt(dp); + if (irq_type) ret = IRQ_WAKE_THREAD; - } return ret; } @@ -721,6 +719,9 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg) u32 irq_type; irq_type = analogix_dp_get_irq_type(dp); + if (irq_type) + analogix_dp_clear_hotplug_interrupts(dp); + if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN || irq_type & DP_IRQ_TYPE_HP_CABLE_OUT) { dev_dbg(dp->dev, "Detected cable status changed!\n"); @@ -728,11 +729,6 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg) drm_helper_hpd_irq_event(dp->drm_dev); } - if (irq_type) { - analogix_dp_clear_hotplug_interrupts(dp); - analogix_dp_unmute_hpd_interrupt(dp); - } - return IRQ_HANDLED; } @@ -1403,10 +1399,11 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data) * that we can get the current state of the GPIO. */ dp->irq = gpiod_to_irq(dp->hpd_gpiod); - irq_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN; + irq_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN | + IRQF_ONESHOT; } else { dp->irq = platform_get_irq(pdev, 0); - irq_flags = IRQF_NO_AUTOEN; + irq_flags = IRQF_NO_AUTOEN | IRQF_ONESHOT; } if (dp->irq == -ENXIO) { -- 2.34.1
