From 3a74265c54f883c847ed8554129baefb3e04f135 Mon Sep 17 00:00:00 2001
From: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Date: Thu, 11 Jun 2020 10:58:43 +0200
Subject: [PATCH] drm/panfrost: Make sure GPU is powered on when reading
GPU_LATEST_FLUSH_ID
Bifrost devices do support the flush reduction feature, so on first job
submit we were trying to read the register while still powered off.
If the GPU is powered off, the feature doesn't bring any benefit, so
don't try to read.
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200611085900.49740-1-tomeu.vizoso@collabora.com
---
drivers/gpu/drm/panfrost/panfrost_gpu.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index f2c1ddc41a9bf..e0f190e438139 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -10,6 +10,7 @@
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include "panfrost_device.h"
#include "panfrost_features.h"
@@ -368,7 +369,16 @@ void panfrost_gpu_fini(struct panfrost_device *pfdev)
u32 panfrost_gpu_get_latest_flush_id(struct panfrost_device *pfdev)
{
- if (panfrost_has_hw_feature(pfdev, HW_FEATURE_FLUSH_REDUCTION))
- return gpu_read(pfdev, GPU_LATEST_FLUSH_ID);
+ u32 flush_id;
+
+ if (panfrost_has_hw_feature(pfdev, HW_FEATURE_FLUSH_REDUCTION)) {
+ /* Flush reduction only makes sense when the GPU is kept powered on between jobs */
+ if (pm_runtime_get_if_in_use(pfdev->dev)) {
+ flush_id = gpu_read(pfdev, GPU_LATEST_FLUSH_ID);
+ pm_runtime_put(pfdev->dev);
+ return flush_id;
+ }
+ }
+
return 0;
}
--
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