[PATCH] i2c: amd-mp2: fix autosuspend cleanup during teardown

[PATCH] i2c: amd-mp2: fix autosuspend cleanup during teardown

[Guangshuo Li]

amd_mp2_pci_probe() calls pm_runtime_use_autosuspend(), but
amd_mp2_pci_remove() does not call the matching
pm_runtime_dont_use_autosuspend() during teardown.

If the autosuspend delay is set to a negative value while autosuspend
is enabled, the runtime PM core increments usage_count to prevent
runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
during teardown, this reference is not dropped.

The documentation for pm_runtime_use_autosuspend() also notes that it
is important to undo it with pm_runtime_dont_use_autosuspend() at
driver exit time, unless runtime PM was initially enabled with
devm_pm_runtime_enable().

Add the missing pm_runtime_dont_use_autosuspend() call to the driver
remove path.

This issue was found by manual code inspection.

Fixes: 529766e0a011 ("i2c: Add drivers for the AMD PCIe MP2 I2C controller")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/i2c/busses/i2c-amd-mp2-pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i2c/busses/i2c-amd-mp2-pci.c b/drivers/i2c/busses/i2c-amd-mp2-pci.c
index 5b41d18b62d3..2b7f7b3cddc5 100644
--- a/drivers/i2c/busses/i2c-amd-mp2-pci.c
+++ b/drivers/i2c/busses/i2c-amd-mp2-pci.c
@@ -371,6 +371,7 @@ static void amd_mp2_pci_remove(struct pci_dev *pci_dev)
 {
 	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
 
+	pm_runtime_dont_use_autosuspend(&pci_dev->dev);
 	pm_runtime_forbid(&pci_dev->dev);
 	pm_runtime_get_noresume(&pci_dev->dev);
 
-- 
2.43.0

Re: [PATCH] i2c: amd-mp2: fix autosuspend cleanup during teardown

[Johan Hovold]

On Sat, Aug 08, 2026 at 11:22:20PM +0800, Guangshuo Li wrote:
> amd_mp2_pci_probe() calls pm_runtime_use_autosuspend(), but
> amd_mp2_pci_remove() does not call the matching
> pm_runtime_dont_use_autosuspend() during teardown.
> 
> If the autosuspend delay is set to a negative value while autosuspend
> is enabled, the runtime PM core increments usage_count to prevent
> runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
> during teardown, this reference is not dropped.

As I've explained elsewhere, this is just misleading. There is no usage
count leak here as the count is balanced whenever the user re-enables
autosuspend through sysfs (by writing a non-negative timeout).

Drivers should clean up after themselves and disable autosuspend, but
this is more of a clean up than a fix and should not be backported.

You've sent upwards of 60 of these in the matter of a just a few days,
some of which have even been picked up. Please send follow-ups (replies
or v2s) as soon as possible to prevent further of these from getting
merged.

> The documentation for pm_runtime_use_autosuspend() also notes that it
> is important to undo it with pm_runtime_dont_use_autosuspend() at
> driver exit time, unless runtime PM was initially enabled with
> devm_pm_runtime_enable().
> 
> Add the missing pm_runtime_dont_use_autosuspend() call to the driver
> remove path.
> 
> This issue was found by manual code inspection.
> 
> Fixes: 529766e0a011 ("i2c: Add drivers for the AMD PCIe MP2 I2C controller")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>

Johan