linux-kernel - [PATCH] drm/msm/a6xx: don't try to set GPU frequency when GMU is suspended

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Date:   Mon, 18 May 2020 23:07:33 -0400
From:   Jonathan Marek <jonathan@...ek.ca>
To:     freedreno@...ts.freedesktop.org
Cc:     Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jordan Crouse <jcrouse@...eaurora.org>,
        "Michael J. Ruhl" <michael.j.ruhl@...el.com>,
        Sharat Masetty <smasetty@...eaurora.org>,
        linux-arm-msm@...r.kernel.org (open list:DRM DRIVER FOR MSM ADRENO GPU),
        dri-devel@...ts.freedesktop.org (open list:DRM DRIVER FOR MSM ADRENO
        GPU), linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] drm/msm/a6xx: don't try to set GPU frequency when GMU is suspended

This fixes changing the frequency in sysfs while suspended, for example
when doing something like this:

cat devfreq/3d00000.gpu/max_freq > devfreq/3d00000.gpu/min_freq

Signed-off-by: Jonathan Marek <jonathan@...ek.ca>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index aec54cde8534..9498803dcad9 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -151,13 +151,20 @@ void a6xx_gmu_set_freq(struct msm_gpu *gpu, unsigned long freq)
 			break;
 
 	gmu->current_perf_index = perf_index;
+	gmu->freq = gmu->gpu_freqs[perf_index];
+
+	/*
+	 * devfreq may try to change frequency target even when suspended
+	 * this can happen when changing frequency through sysfs
+	 * don't try to set freq when suspended, it will be set on resume
+	 */
+	if (!pm_runtime_active(gmu->dev))
+		return;
 
 	if (gmu->legacy)
 		__a6xx_gmu_set_freq(gmu, perf_index);
 	else
 		a6xx_hfi_set_freq(gmu, perf_index);
-
-	gmu->freq = gmu->gpu_freqs[perf_index];
 }
 
 unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu)
-- 
2.26.1