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SubjectRe: [PATCH v2 1/2] driver core: detach device's pm_domain after devres_release_all
On Tue, Aug 15, 2017 at 04:36:56PM +0800, Shawn Lin wrote:
> Move dev_pm_domain_detach after devres_release_all to avoid
> accessing device's registers with genpd been powered off.

So, what is this going to break that is working already today? :)

>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
>
> Changes in v2: None
>
> drivers/base/dd.c | 35 ++++++++++++++++++++++++++++++-----
> drivers/base/platform.c | 18 ++----------------
> 2 files changed, 32 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index ad44b40..13dc0ad 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -25,7 +25,9 @@
> #include <linux/kthread.h>
> #include <linux/wait.h>
> #include <linux/async.h>
> +#include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> +#include <linux/pm_domain.h>
> #include <linux/pinctrl/devinfo.h>
>
> #include "base.h"
> @@ -356,6 +358,8 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> int local_trigger_count = atomic_read(&deferred_trigger_count);
> bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
> !drv->suppress_bind_attrs;
> + struct platform_driver *pdrv;
> + bool do_pm_domain = false;
>
> if (defer_all_probes) {
> /*
> @@ -414,6 +418,16 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> if (ret)
> goto probe_failed;
> } else if (drv->probe) {
> + ret = dev_pm_domain_attach(dev, true);
> + pdrv = to_platform_driver(dev->driver);
> + /* don't fail if just dev_pm_domain_attach failed */
> + if (pdrv->prevent_deferred_probe &&
> + ret == -EPROBE_DEFER) {
> + dev_warn(dev, "probe deferral not supported\n");
> + ret = -ENXIO;
> + goto probe_failed;
> + }
> + do_pm_domain = true;
> ret = drv->probe(dev);
> if (ret)
> goto probe_failed;
> @@ -421,13 +435,17 @@ static int really_probe(struct device *dev, struct device_driver *drv)
>
> if (test_remove) {
> test_remove = false;
> + do_pm_domain = false;
>
> - if (dev->bus->remove)
> + if (dev->bus->remove) {
> dev->bus->remove(dev);
> - else if (drv->remove)
> + } else if (drv->remove) {
> drv->remove(dev);
> -
> + do_pm_domain = true;

Why is this set to true if you have a driver remove function, but not if
you only have a bus remove function? Why the difference?


> + }
> devres_release_all(dev);
> + if (do_pm_domain)
> + dev_pm_domain_detach(dev, true);
> driver_sysfs_remove(dev);
> dev->driver = NULL;
> dev_set_drvdata(dev, NULL);
> @@ -458,6 +476,8 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> pinctrl_bind_failed:
> device_links_no_driver(dev);
> devres_release_all(dev);
> + if (do_pm_domain)
> + dev_pm_domain_detach(dev, true);

Can't you just always call this on the error path?

> driver_sysfs_remove(dev);
> dev->driver = NULL;
> dev_set_drvdata(dev, NULL);
> @@ -818,6 +838,7 @@ int driver_attach(struct device_driver *drv)
> static void __device_release_driver(struct device *dev, struct device *parent)
> {
> struct device_driver *drv;
> + bool do_pm_domain = false;
>
> drv = dev->driver;
> if (drv) {
> @@ -855,15 +876,19 @@ static void __device_release_driver(struct device *dev, struct device *parent)
>
> pm_runtime_put_sync(dev);
>
> - if (dev->bus && dev->bus->remove)
> + if (dev->bus && dev->bus->remove) {
> dev->bus->remove(dev);
> - else if (drv->remove)
> + } else if (drv->remove) {
> + do_pm_domain = true;

Same question here about drivers and bus default functions.

thanks,

greg k-h

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