linux-kernel - [PATCH 17/17] drm/msm/adreno: Relax devfreq tunings

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Message-Id: <20250720-ifpc-support-v1-17-9347aa5bcbd6@oss.qualcomm.com>
Date: Sun, 20 Jul 2025 17:46:18 +0530
From: Akhil P Oommen <akhilpo@....qualcomm.com>
To: Rob Clark <robin.clark@....qualcomm.com>, Sean Paul <sean@...rly.run>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jessica.zhang@....qualcomm.com>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Akhil P Oommen <akhilpo@....qualcomm.com>
Subject: [PATCH 17/17] drm/msm/adreno: Relax devfreq tunings

Relax the devfreq tunings when IFPC feature is supported because there
is no wakeup latency that we have to hide with aggressive dcvs. This
helps to eliminate the very frequent gpu frequency spikes to FMAX even
with common lightweight workloads like UI scrolling. Some profiling
data from X1E which shows the improvement:

DUT: X1E CRD, 1.25Ghz GPU FMAX, 2880x1800@...Hz, Debian Trixie Gnome
Testcase: WebGL aquarium with Chromium

Current dcvs config:

  +--------+--------------+------------+------+
  | Fishes | GPU Load (%) | Freq (Mhz) | FPS  |
  +--------+--------------+------------+------+
  | 1      | 23           | 300        | 120  |
  | 100    | 29           | 300        | 120  |
  | 500    | 41           | 300        | 120  |
  | 1000   | 45           | 390/550    | 120  |
  | 5000   | 50           | 1250       | 120  |
  | 10000  | 93           | 1250       | 120  |
  | 15000  | 100          | 1250       | 87   |
  +--------+--------------+------------+------+

New dcvs config:

  +--------+--------------+------------+------+
  | Fishes | GPU Load (%) | Freq (Mhz) | FPS  |
  +--------+--------------+------------+------+
  | 1      | 23           | 300        | 120  |
  | 100    | 28           | 300        | 120  |
  | 500    | 42           | 300        | 120  |
  | 1000   | 62           | 300        | 120  |
  | 5000   | 84           | 744        | 120  |
  | 10000  | 93           | 1250       | 120  |
  | 15000  | 100          | 1250       | 87   |
  +--------+--------------+------------+------+

Signed-off-by: Akhil P Oommen <akhilpo@....qualcomm.com>
---
 drivers/gpu/drm/msm/msm_gpu_devfreq.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
index 53ef2add5047e7d6b6371af949cab36ce8409372..212963a5b8b57597bf5b01ab90893b01fd9c6e76 100644
--- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c
+++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
@@ -156,6 +156,13 @@ void msm_devfreq_init(struct msm_gpu *gpu)
 	priv->gpu_devfreq_config.upthreshold = 50;
 	priv->gpu_devfreq_config.downdifferential = 10;
 
+	/*
+	 * Relax the tunings when IFPC is supported because there is negligible latency in
+	 * switching power state
+	 */
+	if (to_adreno_gpu(gpu)->info->quirks & ADRENO_QUIRK_IFPC)
+		priv->gpu_devfreq_config.upthreshold = 90;
+
 	mutex_init(&df->lock);
 	df->suspended = true;
 

-- 
2.50.1