[PATCH v6 13/16] drm/panfrost: Avoid cache flush after perfcnt sample in fully coherent systems

From: Adrián Larumbe

Date: Wed Aug 26 2026 - 17:23:15 EST


If the GPU and CPU are fully coherent, then there's no need to flush the
GPU caches after a perfcnt sample is made available.

Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
index ffc77121070e..b3f71d7fd82a 100644
--- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
+++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
@@ -52,7 +52,10 @@ void panfrost_perfcnt_clean_cache_done(struct panfrost_device *pfdev)

void panfrost_perfcnt_sample_done(struct panfrost_device *pfdev)
{
- gpu_write(pfdev, GPU_CMD, GPU_CMD_CLEAN_CACHES);
+ if (pfdev->features.selected_coherency != COHERENCY_ACE)
+ gpu_write(pfdev, GPU_CMD, GPU_CMD_CLEAN_CACHES);
+ else
+ complete(&pfdev->perfcnt->dump_comp);
}

static int panfrost_perfcnt_dump_locked(struct panfrost_device *pfdev)

--
2.55.0