On 18/03/2024 08:58, 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> Reviewed-by: Steven Price <steven.price@xxxxxxx> > --- > 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. The same - I can't test this properly :( Note that the other option (which AFAICT doesn't cause any problems) is to "select PM" rather than depend on it - AIUI the 'select' dependency is considered in the opposite direction by kconfig so won't cause the dependency loop. Of course if there is actually anyone who has a platform which can be built !CONFIG_PM then that won't help. But the inability of anyone to actually properly test this configuration does worry me a little. Steve > --- > 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 > 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, > }, > };
