linux-kernel - [PATCH v2 12/16] drm/msm/a6xx: Fix hangcheck for IFPC

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Message-Id: <20250908-ifpc-support-v2-12-631b1080bf91@oss.qualcomm.com>
Date: Mon, 08 Sep 2025 13:57:05 +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>,
        Antonino Maniscalco <antomani103@...il.com>,
        Neil Armstrong <neil.armstrong@...aro.org>
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 v2 12/16] drm/msm/a6xx: Fix hangcheck for IFPC

>From the hangcheck handler, KMD checks a few registers in GX
domain to see if the GPU made any progress. But it cannot access
those registers when IFPC is enabled. Since HW based hang detection
is pretty decent, lets rely on it instead of these registers when
IFPC is enabled.

Signed-off-by: Akhil P Oommen <akhilpo@....qualcomm.com>
---
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index bba09c02f9809ed24b4a9c30b1eb993ce01c7ec0..61538b6912883a0e7ec7802cf5f5cfc8649ece2b 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -2417,13 +2417,24 @@ static uint32_t a6xx_get_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
 
 static bool a6xx_progress(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
 {
-	struct msm_cp_state cp_state = {
+	struct msm_cp_state cp_state;
+	bool progress;
+
+	/*
+	 * With IFPC, KMD doesn't know whether GX power domain is collapsed
+	 * or not. So, we can't blindly read the below registers in GX domain.
+	 * Lets trust the hang detection in HW and lie to the caller that
+	 * there was progress.
+	 */
+	if (to_adreno_gpu(gpu)->info->quirks & ADRENO_QUIRK_IFPC)
+		return true;
+
+	cp_state = (struct msm_cp_state) {
 		.ib1_base = gpu_read64(gpu, REG_A6XX_CP_IB1_BASE),
 		.ib2_base = gpu_read64(gpu, REG_A6XX_CP_IB2_BASE),
 		.ib1_rem  = gpu_read(gpu, REG_A6XX_CP_IB1_REM_SIZE),
 		.ib2_rem  = gpu_read(gpu, REG_A6XX_CP_IB2_REM_SIZE),
 	};
-	bool progress;
 
 	/*
 	 * Adjust the remaining data to account for what has already been

-- 
2.50.1