On 18/03/2024 8:58 am, Boris Brezillon wrote:
Putting a hard dependency on CONFIG_PM is not possible because of a
circular dependency issue, and it's actually not desirable either. In
order to support this use case, we forcibly resume at init time, and
suspend at unplug time.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202403031944.EOimQ8WK-lkp@xxxxxxxxx/
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
Tested by faking CONFIG_PM=n in the driver (basically commenting
all pm_runtime calls, and making the panthor_device_suspend/resume()
calls unconditional in the panthor_device_unplug/init() path) since
CONFIG_ARCH_ROCKCHIP selects CONFIG_PM. Seems to work fine, but I
can't be 100% sure this will work correctly on a platform that has
CONFIG_PM=n.
---
drivers/gpu/drm/panthor/panthor_device.c | 13 +++++++++++--
drivers/gpu/drm/panthor/panthor_drv.c | 4 +++-
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index 69deb8e17778..ba7aedbb4931 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -87,6 +87,10 @@ void panthor_device_unplug(struct panthor_device *ptdev)
pm_runtime_dont_use_autosuspend(ptdev->base.dev);
pm_runtime_put_sync_suspend(ptdev->base.dev);
+ /* If PM is disabled, we need to call the suspend handler manually. */
+ if (!IS_ENABLED(CONFIG_PM))
+ panthor_device_suspend(ptdev->base.dev);
+
/* Report the unplug operation as done to unblock concurrent
* panthor_device_unplug() callers.
*/
@@ -218,6 +222,13 @@ int panthor_device_init(struct panthor_device *ptdev)
if (ret)
return ret;
+ /* If PM is disabled, we need to call panthor_device_resume() manually. */
+ if (!IS_ENABLED(CONFIG_PM)) {
+ ret = panthor_device_resume(ptdev->base.dev);
+ if (ret)
+ return ret;
+ }
+
ret = panthor_gpu_init(ptdev);
if (ret)
goto err_rpm_put;
@@ -402,7 +413,6 @@ int panthor_device_mmap_io(struct panthor_device *ptdev, struct vm_area_struct *
return 0;
}
-#ifdef CONFIG_PM
int panthor_device_resume(struct device *dev)
{
struct panthor_device *ptdev = dev_get_drvdata(dev);
@@ -547,4 +557,3 @@ int panthor_device_suspend(struct device *dev)
mutex_unlock(&ptdev->pm.mmio_lock);
return ret;
}
-#endif
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index ff484506229f..2ea6a9f436db 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1407,17 +1407,19 @@ static const struct of_device_id dt_match[] = {
};
MODULE_DEVICE_TABLE(of, dt_match);
+#ifdef CONFIG_PM
This #ifdef isn't necessary, and in fact will break the !PM build -
pm_ptr() already takes care of allowing the compiler to optimise out the
ops structure itself without any further annotations.
Thanks,
Robin.
static DEFINE_RUNTIME_DEV_PM_OPS(panthor_pm_ops,
panthor_device_suspend,
panthor_device_resume,
NULL);
+#endif
static struct platform_driver panthor_driver = {
.probe = panthor_probe,
.remove_new = panthor_remove,
.driver = {
.name = "panthor",
- .pm = &panthor_pm_ops,
+ .pm = pm_ptr(&panthor_pm_ops),
.of_match_table = dt_match,
},
};
