queue-6.19/drm-panthor-fix-the-full_tick-check.patch

From 97d2c5b4c7f1d037619edab089209997c007ac9f Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Fri, 28 Nov 2025 10:48:34 +0100
Subject: drm/panthor: Fix the full_tick check

From: Boris Brezillon <boris.brezillon@collabora.com>

[ Upstream commit a3c2d0b40b108bd45d44f6c1dfa33c39d577adcd ]

We have a full tick when the remaining time to the next tick is zero,
not the other way around. Declare a full_tick variable so we don't get
that test wrong in other places.

v2:
- Add R-b

v3:
- Collect R-b

Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block")
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: https://patch.msgid.link/20251128094839.3856402-4-boris.brezillon@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/panthor/panthor_sched.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index a6b8024e1a3cd..3b52c23849339 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -2483,6 +2483,7 @@ static void tick_work(struct work_struct *work)
 	u64 remaining_jiffies = 0, resched_delay;
 	u64 now = get_jiffies_64();
 	int prio, ret, cookie;
+	bool full_tick;
 
 	if (!drm_dev_enter(&ptdev->base, &cookie))
 		return;
@@ -2494,15 +2495,17 @@ static void tick_work(struct work_struct *work)
 	if (time_before64(now, sched->resched_target))
 		remaining_jiffies = sched->resched_target - now;
 
+	full_tick = remaining_jiffies == 0;
+
 	mutex_lock(&sched->lock);
 	if (panthor_device_reset_is_pending(sched->ptdev))
 		goto out_unlock;
 
-	tick_ctx_init(sched, &ctx, remaining_jiffies != 0);
+	tick_ctx_init(sched, &ctx, full_tick);
 	if (ctx.csg_upd_failed_mask)
 		goto out_cleanup_ctx;
 
-	if (remaining_jiffies) {
+	if (!full_tick) {
 		/* Scheduling forced in the middle of a tick. Only RT groups
 		 * can preempt non-RT ones. Currently running RT groups can't be
 		 * preempted.
-- 
2.51.0