From a4447c0693830d5ecadd6e755cb7fdc55d86aacc Mon Sep 17 00:00:00 2001 From: Pushpendra Singh Date: Wed, 8 Jul 2026 12:53:39 +0530 Subject: [PATCH] firmware: arm_scmi: Rate-limit queue-full warnings in IRQ context The scmi_notify() function is called from interrupt context to queue received notification events onto a per-protocol kfifo. When the kfifo is full, it logs a warning via dev_warn() for every dropped event. Under conditions where the platform sends a burst of SCMI notifications faster than the deferred worker can drain the queue, this results in a flood of dev_warn() calls from IRQ context. Each call acquires the console lock and may execute blocking console writes, causing the CPU to be held in interrupt context for an extended period and leading to observable system stalls. Fix this by switching to dev_warn_ratelimited() to limit the frequency of log messages when the notification queue is full. This reduces console overhead in interrupt context and prevents CPU stalls caused by excessive logging, while still preserving diagnostic visibility. Fixes: bd31b249692e ("firmware: arm_scmi: Add notification dispatch and delivery") Signed-off-by: Pushpendra Singh Link: https://patch.msgid.link/20260708072339.3021140-1-pushpendra.singh@oss.qualcomm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/notify.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c index 40ec184eedae..0a192cf2deab 100644 --- a/drivers/firmware/arm_scmi/notify.c +++ b/drivers/firmware/arm_scmi/notify.c @@ -600,9 +600,9 @@ int scmi_notify(const struct scmi_handle *handle, u8 proto_id, u8 evt_id, return -EINVAL; } if (kfifo_avail(&r_evt->proto->equeue.kfifo) < sizeof(eh) + len) { - dev_warn(handle->dev, - "queue full, dropping proto_id:%d evt_id:%d ts:%lld\n", - proto_id, evt_id, ktime_to_ns(ts)); + dev_warn_ratelimited(handle->dev, + "queue full, dropping proto_id:%d evt_id:%d ts:%lld\n", + proto_id, evt_id, ktime_to_ns(ts)); return -ENOMEM; }