You'll get garbage measurements if the registers always read back
0xdeadbeef

Signed-off-by: Eric Anholt <e...@anholt.net>
---
 drivers/gpu/drm/v3d/v3d_debugfs.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/v3d/v3d_debugfs.c 
b/drivers/gpu/drm/v3d/v3d_debugfs.c
index eb2b2d2f8553..a24af2d2f574 100644
--- a/drivers/gpu/drm/v3d/v3d_debugfs.c
+++ b/drivers/gpu/drm/v3d/v3d_debugfs.c
@@ -187,6 +187,11 @@ static int v3d_measure_clock(struct seq_file *m, void 
*unused)
        uint32_t cycles;
        int core = 0;
        int measure_ms = 1000;
+       int ret;
+
+       ret = pm_runtime_get_sync(v3d->dev);
+       if (ret < 0)
+               return ret;
 
        if (v3d->ver >= 40) {
                V3D_CORE_WRITE(core, V3D_V4_PCTR_0_SRC_0_3,
@@ -210,6 +215,9 @@ static int v3d_measure_clock(struct seq_file *m, void 
*unused)
                   cycles / (measure_ms * 1000),
                   (cycles / (measure_ms * 100)) % 10);
 
+       pm_runtime_mark_last_busy(v3d->dev);
+       pm_runtime_put_autosuspend(v3d->dev);
+
        return 0;
 }
 
-- 
2.20.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

Reply via email to