linux-kernel - [PATCH v2 02/21] drm/msm/a6xx: Fix the gemnoc workaround

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Message-Id: <20251110-kaana-gpu-support-v2-2-bef18acd5e94@oss.qualcomm.com>
Date: Mon, 10 Nov 2025 22:07:08 +0530
From: Akhil P Oommen <akhilpo@....qualcomm.com>
To: Rob Clark <robin.clark@....qualcomm.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Sean Paul <sean@...rly.run>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jesszhan0024@...il.com>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Jonathan Marek <jonathan@...ek.ca>,
        Jordan Crouse <jordan@...micpenguin.net>,
        Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Connor Abbott <cwabbott0@...il.com>
Cc: linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, iommu@...ts.linux.dev,
        devicetree@...r.kernel.org, Akhil P Oommen <akhilpo@....qualcomm.com>
Subject: [PATCH v2 02/21] drm/msm/a6xx: Fix the gemnoc workaround

Correct the register offset and enable this workaround for all A7x
and newer GPUs to match the recommendation. Also, downstream does this
w/a after moving the fence to allow mode. So do the same.

Fixes: dbfbb376b50c ("drm/msm/a6xx: Add A621 support")
Signed-off-by: Akhil P Oommen <akhilpo@....qualcomm.com>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 4e6dc16e4a4c..605bb55de8d5 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -485,8 +485,9 @@ static void a6xx_gemnoc_workaround(struct a6xx_gmu *gmu)
 	 * in the power down sequence not being fully executed. That in turn can
 	 * prevent CX_GDSC from collapsing. Assert Qactive to avoid this.
 	 */
-	if (adreno_is_a621(adreno_gpu) || adreno_is_7c3(adreno_gpu))
-		gmu_write(gmu, REG_A6XX_GMU_AO_AHB_FENCE_CTRL, BIT(0));
+	if (adreno_is_a7xx(adreno_gpu) || (adreno_is_a621(adreno_gpu) ||
+				adreno_is_7c3(adreno_gpu)))
+		gmu_write(gmu, REG_A6XX_GPU_GMU_CX_GMU_CX_FALNEXT_INTF, BIT(0));
 }
 
 /* Let the GMU know that we are about to go into slumber */
@@ -522,10 +523,9 @@ static int a6xx_gmu_notify_slumber(struct a6xx_gmu *gmu)
 	}
 
 out:
-	a6xx_gemnoc_workaround(gmu);
-
 	/* Put fence into allow mode */
 	gmu_write(gmu, REG_A6XX_GMU_AO_AHB_FENCE_CTRL, 0);
+	a6xx_gemnoc_workaround(gmu);
 	return ret;
 }
 

-- 
2.51.0