[PATCH v2 09/11] drm/panthor: Process FW events in IRQ context

From: Boris Brezillon

Date: Tue May 12 2026 - 07:39:14 EST


Now that everything is set to allow processing FW events in IRQ context,
go for it. This should reduce the dma_fence signaling latency.

Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panthor/panthor_fw.c | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index f5e0ceca4130..8cfebf180de7 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -1087,9 +1087,29 @@ static void panthor_job_irq_handler(struct panthor_irq *pirq, u32 status)
}
}

-static irqreturn_t panthor_job_irq_threaded_handler(int irq, void *data)
+static irqreturn_t panthor_job_irq_raw_handler(int irq, void *data)
{
- return panthor_irq_default_threaded_handler(data, panthor_job_irq_handler);
+ struct panthor_irq *pirq = data;
+
+ if (!gpu_read(pirq->iomem, INT_STAT))
+ return IRQ_NONE;
+
+ scoped_guard(spinlock_irqsave, &pirq->mask_lock) {
+ if (pirq->state != PANTHOR_IRQ_STATE_ACTIVE)
+ return IRQ_NONE;
+
+ pirq->state = PANTHOR_IRQ_STATE_PROCESSING;
+ }
+
+ /* We can use INT_STAT here, because we didn't mask the IRQs. */
+ panthor_job_irq_handler(pirq, gpu_read(pirq->iomem, INT_STAT));
+
+ scoped_guard(spinlock_irqsave, &pirq->mask_lock) {
+ if (pirq->state == PANTHOR_IRQ_STATE_PROCESSING)
+ pirq->state = PANTHOR_IRQ_STATE_ACTIVE;
+ }
+
+ return IRQ_HANDLED;
}

static int panthor_fw_start(struct panthor_device *ptdev)
@@ -1489,8 +1509,7 @@ int panthor_fw_init(struct panthor_device *ptdev)

ret = panthor_irq_request(ptdev, &fw->irq, irq, 0,
ptdev->iomem + JOB_INT_BASE, "job",
- panthor_irq_default_raw_handler,
- panthor_job_irq_threaded_handler);
+ panthor_job_irq_raw_handler, NULL);
if (ret) {
drm_err(&ptdev->base, "failed to request job irq");
return ret;

--
2.54.0