[PATCH 6.18 169/641] drm/panthor: Fix the full_tick check

Greg Kroah-Hartman
2026-02-25T01:44:58Z

6.18-stable review patch. If anyone has any objections, please let me know.

------------------

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 881a07ffbabc8..6e4667cbe1b82 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -2387,6 +2387,7 @@ 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;
@@ -2398,15 +2399,17 @@ 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