linux-kernel - [PATCH 5.8 311/633] drm/panfrost: increase readl_relaxed_poll

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Message-Id: <20201027135537.266820407@linuxfoundation.org>
Date:   Tue, 27 Oct 2020 14:50:54 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Steven Price <steven.price@....com>,
        Christian Hewitt <christianshewitt@...il.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.8 311/633] drm/panfrost: increase readl_relaxed_poll_timeout values

From: Christian Hewitt <christianshewitt@...il.com>

[ Upstream commit c2df75ad2a9f205820e4bc0db936d3d9af3da1ae ]

Amlogic SoC devices report the following errors frequently causing excessive
dmesg log spam and early log rotataion, although the errors appear to be
harmless as everything works fine:

[    7.202702] panfrost ffe40000.gpu: error powering up gpu L2
[    7.203760] panfrost ffe40000.gpu: error powering up gpu shader

ARM staff have advised increasing the timeout values to eliminate the errors
in most normal scenarios, and testing with several different G31/G52 devices
shows 20000 to be a reliable value.

Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver")
Suggested-by: Steven Price <steven.price@....com>
Signed-off-by: Christian Hewitt <christianshewitt@...il.com>
Reviewed-by: Steven Price <steven.price@....com>
Signed-off-by: Steven Price <steven.price@....com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201008141738.13560-1-christianshewitt@gmail.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/panfrost/panfrost_gpu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index 689b92893e0e1..dfe4c9151eaf2 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -309,13 +309,13 @@ void panfrost_gpu_power_on(struct panfrost_device *pfdev)
 	/* Just turn on everything for now */
 	gpu_write(pfdev, L2_PWRON_LO, pfdev->features.l2_present);
 	ret = readl_relaxed_poll_timeout(pfdev->iomem + L2_READY_LO,
-		val, val == pfdev->features.l2_present, 100, 1000);
+		val, val == pfdev->features.l2_present, 100, 20000);
 	if (ret)
 		dev_err(pfdev->dev, "error powering up gpu L2");
 
 	gpu_write(pfdev, SHADER_PWRON_LO, pfdev->features.shader_present);
 	ret = readl_relaxed_poll_timeout(pfdev->iomem + SHADER_READY_LO,
-		val, val == pfdev->features.shader_present, 100, 1000);
+		val, val == pfdev->features.shader_present, 100, 20000);
 	if (ret)
 		dev_err(pfdev->dev, "error powering up gpu shader");
 
-- 
2.25.1