[PATCH] drm/amd: use drm_kms_helper_poll_fini in amdgpu_device_suspend to avoid warning

[Chen, Guchun]

Hi Bert,

Thanks for your patch. As we will can drm_kms_helper_poll_enable in resume, so it may not make sense using drm_kms_helper_poll_fini in suspend, from code pairing perspective.

For your case, is it possible to fix the problem by limiting the access of drm_kms_helper_poll_disable with checking mode_config_initialized in adev structure? We can get rid of the code change in drm core in this way.

Regards,
Guchun

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Bert Karwatzki
Sent: Friday, February 24, 2023 4:52 AM
To: amd-gfx at lists.freedesktop.org
Subject: Re: [PATCH] drm/amd: use drm_kms_helper_poll_fini in amdgpu_device_suspend to avoid warning

When drm_kms_helper_poll_disable is used in amdgpu_device_suspend without drm_kms_helper_poll_init having been called it causes a warning in __flush_work:
https://gitlab.freedesktop.org/drm/amd/-/issues/2411
To avoid this one can use drm_kms_helper_poll_fini instead:
Send a second time because Evolution seems to have garbled the first patch. 

From 51cba3ae1e9f557cca8e37eb43b9b9310d0d504d Mon Sep 17 00:00:00 2001
From: Bert Karwatzki <spasswolf at web.de>
Date: Thu, 16 Feb 2023 10:34:11 +0100
Subject: [PATCH] Use drm_kms_helper_poll_fini instead of
 drm_kms_helper_poll_disable in amdgpu_device.c to avoid a warning from
 __flush_work.

Signed-off-by: Bert Karwatzki <spasswolf at web.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
 drivers/gpu/drm/drm_probe_helper.c         | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index b325f7039e0e..dc9e9868a84b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4145,7 +4145,7 @@ int amdgpu_device_suspend(struct drm_device *dev, bool fbcon)
        if (amdgpu_acpi_smart_shift_update(dev, AMDGPU_SS_DEV_D3))
                DRM_WARN("smart shift update failed\n");
 
-       drm_kms_helper_poll_disable(dev);
+       drm_kms_helper_poll_fini(dev);
 
        if (fbcon)
                drm_fb_helper_set_suspend_unlocked(adev_to_drm(adev)-
> fb_helper, true);
diff --git a/drivers/gpu/drm/drm_probe_helper.c
b/drivers/gpu/drm/drm_probe_helper.c
index 8127be134c39..105d00d5ebf3 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -842,9 +842,10 @@ EXPORT_SYMBOL(drm_kms_helper_is_poll_worker);
  *
  * This function disables the output polling work.
  *
- * Drivers can call this helper from their device suspend implementation. It is
- * not an error to call this even when output polling isn't enabled or already
- * disabled. Polling is re-enabled by calling drm_kms_helper_poll_enable().
+ * Drivers can call this helper from their device suspend
implementation. If it
+ * is not known if drm_kms_helper_poll_init has been called before the
driver
+ * should use drm_kms_helper_poll_fini_instead.
+ * Polling is re-enabled by calling drm_kms_helper_poll_enable().
  *
  * Note that calls to enable and disable polling must be strictly ordered, which
  * is automatically the case when they're only call from suspend/resume