linux-kernel - [RFT PATCH v2 07/12] drm/amdgpu: Call drm_atomic_helper

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Date:   Thu, 21 Sep 2023 12:26:50 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     dri-devel@...ts.freedesktop.org, Maxime Ripard <mripard@...nel.org>
Cc:     Douglas Anderson <dianders@...omium.org>, Bokun.Zhang@....com,
        Hawking.Zhang@....com, James.Zhu@....com, Victor.Zhao@....com,
        Xinhui.Pan@....com, airlied@...il.com, alexander.deucher@....com,
        amd-gfx@...ts.freedesktop.org, christian.koenig@....com,
        daniel@...ll.ch, felix.kuehling@....com, jim.cromie@...il.com,
        le.ma@....com, lijo.lazar@....com, linux-kernel@...r.kernel.org,
        maarten.lankhorst@...ux.intel.com, mario.limonciello@....com,
        mdaenzer@...hat.com, shiwu.zhang@....com,
        srinivasan.shanmugam@....com, tzimmermann@...e.de
Subject: [RFT PATCH v2 07/12] drm/amdgpu: Call drm_atomic_helper_shutdown() at shutdown time

Based on grepping through the source code this driver appears to be
missing a call to drm_atomic_helper_shutdown() at system shutdown
time. Among other things, this means that if a panel is in use that it
won't be cleanly powered off at system shutdown time.

The fact that we should call drm_atomic_helper_shutdown() in the case
of OS shutdown/restart comes straight out of the kernel doc "driver
instance overview" in drm_drv.c.

Suggested-by: Maxime Ripard <mripard@...nel.org>
Signed-off-by: Douglas Anderson <dianders@...omium.org>
---
This commit is only compile-time tested.

...and further, I'd say that this patch is more of a plea for help
than a patch I think is actually right. I'm _fairly_ certain that
drm/amdgpu needs this call at shutdown time but the logic is a bit
hard for me to follow. I'd appreciate if anyone who actually knows
what this should look like could illuminate me, or perhaps even just
post a patch themselves!

(no changes since v1)

 drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 10 ++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    |  2 ++
 3 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 8f2255b3a38a..cfcff0b37466 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1104,6 +1104,7 @@ static inline struct amdgpu_device *amdgpu_ttm_adev(struct ttm_device *bdev)
 int amdgpu_device_init(struct amdgpu_device *adev,
 		       uint32_t flags);
 void amdgpu_device_fini_hw(struct amdgpu_device *adev);
+void amdgpu_device_shutdown_hw(struct amdgpu_device *adev);
 void amdgpu_device_fini_sw(struct amdgpu_device *adev);
 
 int amdgpu_gpu_wait_for_idle(struct amdgpu_device *adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index a2cdde0ca0a7..fa5925c2092d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4247,6 +4247,16 @@ void amdgpu_device_fini_hw(struct amdgpu_device *adev)
 
 }
 
+void amdgpu_device_shutdown_hw(struct amdgpu_device *adev)
+{
+	if (adev->mode_info.mode_config_initialized) {
+		if (!drm_drv_uses_atomic_modeset(adev_to_drm(adev)))
+			drm_helper_force_disable_all(adev_to_drm(adev));
+		else
+			drm_atomic_helper_shutdown(adev_to_drm(adev));
+	}
+}
+
 void amdgpu_device_fini_sw(struct amdgpu_device *adev)
 {
 	int idx;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index e90f730eb715..3a7cbff111d1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2333,6 +2333,8 @@ amdgpu_pci_shutdown(struct pci_dev *pdev)
 	struct drm_device *dev = pci_get_drvdata(pdev);
 	struct amdgpu_device *adev = drm_to_adev(dev);
 
+	amdgpu_device_shutdown_hw(adev);
+
 	if (amdgpu_ras_intr_triggered())
 		return;
 
-- 
2.42.0.515.g380fc7ccd1-goog