[PATCH] drm/msm/devfreq: Restrict idle clamping to a618 for now

Rob Clark
2021-10-18T15:31:49Z

From: Rob Clark <robdclark@chromium.org>

Until we better understand the stability issues caused by frequent
frequency changes, lets limit them to a618.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
Caleb/John, I think this should help as a workaround for the power
instability issues on a630.. could you give it a try?

drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 7 +++++++
drivers/gpu/drm/msm/msm_gpu.h | 4 ++++
drivers/gpu/drm/msm/msm_gpu_devfreq.c | 3 ++-
3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 33da25b81615..267a880811d6 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1838,6 +1838,13 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
adreno_cmp_rev(ADRENO_REV(6, 3, 5, ANY_ID), info->rev)))
adreno_gpu->base.hw_apriv = true;

+ /*
+ * For now only clamp to idle freq for devices where this is known not
+ * to cause power supply issues:
+ */
+ if (info && (info->revn == 618))
+ gpu->clamp_to_idle = true;
+
a6xx_llc_slices_init(pdev, a6xx_gpu);

ret = a6xx_set_supported_hw(&pdev->dev, config->rev);
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 59870095ea41..59cdd00b69d0 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -210,6 +210,10 @@ struct msm_gpu {
uint32_t suspend_count;

struct msm_gpu_state *crashstate;
+
+ /* Enable clamping to idle freq when inactive: */
+ bool clamp_to_idle;
+
/* True if the hardware supports expanded apriv (a650 and newer) */
bool hw_apriv;

diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
index d32b729b4616..8b7473f69cb8 100644
--- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c
+++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
@@ -214,7 +214,8 @@ static void msm_devfreq_idle_work(struct kthread_work *work)

idle_freq = get_freq(gpu);

- msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);
+ if (gpu->clamp_to_idle)
+ msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);

df->idle_time = ktime_get();
df->idle_freq = idle_freq;
--
2.31.1