linux-kernel - [PATCH] drm/msm/adreno: Defer enabling runpm until hw

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Date:   Mon, 13 Jun 2022 11:20:30 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        Rob Clark <robdclark@...omium.org>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>,
        Jonathan Marek <jonathan@...ek.ca>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Vladimir Lypak <vladimir.lypak@...il.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Dmitry Osipenko <dmitry.osipenko@...labora.com>,
        Christian König <christian.koenig@....com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] drm/msm/adreno: Defer enabling runpm until hw_init()

From: Rob Clark <robdclark@...omium.org>

To avoid preventing the display from coming up before the rootfs is
mounted, without resorting to packing fw in the initrd, the GPU has
this limbo state where the device is probed, but we aren't ready to
start sending commands to it.  This is particularly problematic for
a6xx, since the GMU (which requires fw to be loaded) is the one that
is controlling the power/clk/icc votes.

So defer enabling runpm until we are ready to call gpu->hw_init(),
as that is a point where we know we have all the needed fw and are
ready to start sending commands to the coproc's.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/gpu/drm/msm/adreno/adreno_device.c | 6 ++++++
 drivers/gpu/drm/msm/adreno/adreno_gpu.c    | 1 -
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index 8706bcdd1472..7cef8ae73c71 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -415,6 +415,12 @@ struct msm_gpu *adreno_load_gpu(struct drm_device *dev)
 	if (ret)
 		return NULL;
 
+	/*
+	 * Now that we have firmware loaded, and are ready to begin
+	 * booting the gpu, go ahead and enable runpm:
+	 */
+	pm_runtime_enable(&pdev->dev);
+
 	/* Make sure pm runtime is active and reset any previous errors */
 	pm_runtime_set_active(&pdev->dev);
 
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 4e665c806a14..e1aef4875e2f 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -1042,7 +1042,6 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 	pm_runtime_set_autosuspend_delay(dev,
 		adreno_gpu->info->inactive_period);
 	pm_runtime_use_autosuspend(dev);
-	pm_runtime_enable(dev);
 
 	return msm_gpu_init(drm, pdev, &adreno_gpu->base, &funcs->base,
 			gpu_name, &adreno_gpu_config);
-- 
2.36.1