linux-kernel - [PATCH v3 4/7] drm/msm/a5xx: Reset VBIF before PC only on A510 and A530

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Message-Id: <20210113183339.446239-5-angelogioacchino.delregno@somainline.org>
Date:   Wed, 13 Jan 2021 19:33:36 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>
To:     robdclark@...il.com
Cc:     sean@...rly.run, airlied@...ux.ie, daniel@...ll.ch,
        jcrouse@...eaurora.org, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, phone-devel@...r.kernel.org,
        konrad.dybcio@...ainline.org, marijn.suijten@...ainline.org,
        martin.botka@...ainline.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>
Subject: [PATCH v3 4/7] drm/msm/a5xx: Reset VBIF before PC only on A510 and A530

Resetting the VBIF before power collapse is done to avoid getting
bogus FIFO entries during the suspend sequence or subsequent resume,
but this is doable only on Adreno 510 and Adreno 530, as the other
units will tendentially lock up.
Especially on Adreno 508, the GPU will show lockups and very bad
slownesses after processing the first frame.

Avoiding to execute the RBBM SW Reset before suspend will stop the
lockup issue from happening on at least Adreno 508/509/512.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...ainline.org>
Reviewed-by: Jordan Crouse <jcrouse@...eaurora.org>
---
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index 04ffd84c1190..66980f4cd93e 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -1360,10 +1360,12 @@ static int a5xx_pm_suspend(struct msm_gpu *gpu)
 
 	/*
 	 * Reset the VBIF before power collapse to avoid issue with FIFO
-	 * entries
+	 * entries on Adreno A510 and A530 (the others will tend to lock up)
 	 */
-	gpu_write(gpu, REG_A5XX_RBBM_BLOCK_SW_RESET_CMD, 0x003C0000);
-	gpu_write(gpu, REG_A5XX_RBBM_BLOCK_SW_RESET_CMD, 0x00000000);
+	if (adreno_is_a510(adreno_gpu) || adreno_is_a530(adreno_gpu)) {
+		gpu_write(gpu, REG_A5XX_RBBM_BLOCK_SW_RESET_CMD, 0x003C0000);
+		gpu_write(gpu, REG_A5XX_RBBM_BLOCK_SW_RESET_CMD, 0x00000000);
+	}
 
 	ret = msm_gpu_pm_suspend(gpu);
 	if (ret)
-- 
2.29.2