diff mbox series

[v1] pmdomain: imx8m-blk-ctrl: fix suspend/resume order

Message ID 20240418155151.355133-1-ivitro@gmail.com (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series [v1] pmdomain: imx8m-blk-ctrl: fix suspend/resume order | expand

Commit Message

Vitor Soares April 18, 2024, 3:51 p.m. UTC
From: Vitor Soares <vitor.soares@toradex.com>

During the probe, the genpd power_dev is added to the dpm_list after
blk_ctrl due to its parent/child relationship. Making the blk_ctrl
suspend after and resume before the genpd power_dev.

As a consequence, the system hangs when resuming the VPU due to the
power domain dependency.

To ensure the proper suspend/resume order, add a device link betweem
blk_ctrl and genpd power_dev. It guarantees genpd power_dev is suspended
after and resumed before blk-ctrl.

Cc: <stable@vger.kernel.org>
Closes: https://lore.kernel.org/all/fccbb040330a706a4f7b34875db1d896a0bf81c8.camel@gmail.com/
Link: https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/
Fixes: 2684ac05a8c4 ("soc: imx: add i.MX8M blk-ctrl driver")
Suggested-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
---

This is a new patch, but is a follow-up of:
https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/

As suggested by Lucas, we are addressing this PM issue in the imx8m-blk-ctrl
driver instead of in the imx8mm.dtsi.

 drivers/pmdomain/imx/imx8m-blk-ctrl.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Comments

Markus Elfring April 18, 2024, 4:24 p.m. UTC | #1
>                                         …, add a device link betweem
> blk_ctrl and genpd power_dev. …

I hope that a typo will be avoided in this change description for the final commit.

Regards,
Markus
Vitor Soares April 18, 2024, 4:50 p.m. UTC | #2
Hi Markus,


On Thu, 2024-04-18 at 18:24 +0200, Markus Elfring wrote:
> >                                         …, add a device link betweem
> > blk_ctrl and genpd power_dev. …
> 
> I hope that a typo will be avoided in this change description for the final commit.
> 

Thanks for you feedback.
I will fix it next version.

Best regards,
Vitor Soares

> Regards,
> Markus
Francesco Dolcini May 8, 2024, 5:40 p.m. UTC | #3
On Thu, Apr 18, 2024 at 04:51:51PM +0100, Vitor Soares wrote:
> From: Vitor Soares <vitor.soares@toradex.com>
> 
> During the probe, the genpd power_dev is added to the dpm_list after
> blk_ctrl due to its parent/child relationship. Making the blk_ctrl
> suspend after and resume before the genpd power_dev.
> 
> As a consequence, the system hangs when resuming the VPU due to the
> power domain dependency.
> 
> To ensure the proper suspend/resume order, add a device link betweem
> blk_ctrl and genpd power_dev. It guarantees genpd power_dev is suspended
> after and resumed before blk-ctrl.
> 

Cc: Adam Ford

Francesco
Adam Ford May 8, 2024, 5:43 p.m. UTC | #4
On Wed, May 8, 2024 at 12:40 PM Francesco Dolcini <francesco@dolcini.it> wrote:
>
> On Thu, Apr 18, 2024 at 04:51:51PM +0100, Vitor Soares wrote:
> > From: Vitor Soares <vitor.soares@toradex.com>
> >
> > During the probe, the genpd power_dev is added to the dpm_list after
> > blk_ctrl due to its parent/child relationship. Making the blk_ctrl
> > suspend after and resume before the genpd power_dev.
> >
> > As a consequence, the system hangs when resuming the VPU due to the
> > power domain dependency.
> >
> > To ensure the proper suspend/resume order, add a device link betweem
> > blk_ctrl and genpd power_dev. It guarantees genpd power_dev is suspended
> > after and resumed before blk-ctrl.
> >
>
> Cc: Adam Ford

Thanks!  This is what I was thinking from the other thread.  I just
didn't see this one.


adam
>
> Francesco
>
Lucas Stach May 8, 2024, 5:46 p.m. UTC | #5
Am Donnerstag, dem 18.04.2024 um 16:51 +0100 schrieb Vitor Soares:
> From: Vitor Soares <vitor.soares@toradex.com>
> 
> During the probe, the genpd power_dev is added to the dpm_list after
> blk_ctrl due to its parent/child relationship. Making the blk_ctrl
> suspend after and resume before the genpd power_dev.
> 
> As a consequence, the system hangs when resuming the VPU due to the
> power domain dependency.
> 
> To ensure the proper suspend/resume order, add a device link betweem
> blk_ctrl and genpd power_dev. It guarantees genpd power_dev is suspended
> after and resumed before blk-ctrl.
> 
> Cc: <stable@vger.kernel.org>
> Closes: https://lore.kernel.org/all/fccbb040330a706a4f7b34875db1d896a0bf81c8.camel@gmail.com/
> Link: https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/
> Fixes: 2684ac05a8c4 ("soc: imx: add i.MX8M blk-ctrl driver")
> Suggested-by: Lucas Stach <l.stach@pengutronix.de>
> Signed-off-by: Vitor Soares <vitor.soares@toradex.com>

Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

> ---
> 
> This is a new patch, but is a follow-up of:
> https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/
> 
> As suggested by Lucas, we are addressing this PM issue in the imx8m-blk-ctrl
> driver instead of in the imx8mm.dtsi.
> 
>  drivers/pmdomain/imx/imx8m-blk-ctrl.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/pmdomain/imx/imx8m-blk-ctrl.c b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> index ca942d7929c2..cd0d2296080d 100644
> --- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> +++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> @@ -283,6 +283,20 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
>  			goto cleanup_pds;
>  		}
>  
> +		/*
> +		 * Enforce suspend/resume ordering by making genpd power_dev a
> +		 * provider of blk-ctrl. Genpd power_dev is suspended after and
> +		 * resumed before blk-ctrl.
> +		 */
> +		if (!device_link_add(dev, domain->power_dev, DL_FLAG_STATELESS)) {
> +			ret = -EINVAL;
> +			dev_err_probe(dev, ret,
> +				      "failed to link to %s\n", data->name);
> +			pm_genpd_remove(&domain->genpd);
> +			dev_pm_domain_detach(domain->power_dev, true);
> +			goto cleanup_pds;
> +		}
> +
>  		/*
>  		 * We use runtime PM to trigger power on/off of the upstream GPC
>  		 * domain, as a strict hierarchical parent/child power domain
> @@ -324,6 +338,7 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
>  	of_genpd_del_provider(dev->of_node);
>  cleanup_pds:
>  	for (i--; i >= 0; i--) {
> +		device_link_remove(dev, bc->domains[i].power_dev);
>  		pm_genpd_remove(&bc->domains[i].genpd);
>  		dev_pm_domain_detach(bc->domains[i].power_dev, true);
>  	}
> @@ -343,6 +358,7 @@ static void imx8m_blk_ctrl_remove(struct platform_device *pdev)
>  	for (i = 0; bc->onecell_data.num_domains; i++) {
>  		struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
>  
> +		device_link_remove(&pdev->dev, domain->power_dev);
>  		pm_genpd_remove(&domain->genpd);
>  		dev_pm_domain_detach(domain->power_dev, true);
>  	}
Ulf Hansson May 10, 2024, 9:34 a.m. UTC | #6
On Thu, 18 Apr 2024 at 17:52, Vitor Soares <ivitro@gmail.com> wrote:
>
> From: Vitor Soares <vitor.soares@toradex.com>
>
> During the probe, the genpd power_dev is added to the dpm_list after
> blk_ctrl due to its parent/child relationship. Making the blk_ctrl
> suspend after and resume before the genpd power_dev.
>
> As a consequence, the system hangs when resuming the VPU due to the
> power domain dependency.
>
> To ensure the proper suspend/resume order, add a device link betweem
> blk_ctrl and genpd power_dev. It guarantees genpd power_dev is suspended
> after and resumed before blk-ctrl.

Before discussing $subject patch, would you mind explaining to me why
imx8m-blk-ctrl needs to use the ->suspend() callback at all?

Looking closer at that code (imx8m_blk_ctrl_suspend()), it calls
pm_runtime_get_sync() for devices to power on "everything". Why isn't
that managed by the consumer drivers (on a case by case basis) that
are managing the devices that are attached to the genpds instead?

Kind regards
Uffe

>
> Cc: <stable@vger.kernel.org>
> Closes: https://lore.kernel.org/all/fccbb040330a706a4f7b34875db1d896a0bf81c8.camel@gmail.com/
> Link: https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/
> Fixes: 2684ac05a8c4 ("soc: imx: add i.MX8M blk-ctrl driver")
> Suggested-by: Lucas Stach <l.stach@pengutronix.de>
> Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
> ---
>
> This is a new patch, but is a follow-up of:
> https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/
>
> As suggested by Lucas, we are addressing this PM issue in the imx8m-blk-ctrl
> driver instead of in the imx8mm.dtsi.
>
>  drivers/pmdomain/imx/imx8m-blk-ctrl.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/drivers/pmdomain/imx/imx8m-blk-ctrl.c b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> index ca942d7929c2..cd0d2296080d 100644
> --- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> +++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> @@ -283,6 +283,20 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
>                         goto cleanup_pds;
>                 }
>
> +               /*
> +                * Enforce suspend/resume ordering by making genpd power_dev a
> +                * provider of blk-ctrl. Genpd power_dev is suspended after and
> +                * resumed before blk-ctrl.
> +                */
> +               if (!device_link_add(dev, domain->power_dev, DL_FLAG_STATELESS)) {
> +                       ret = -EINVAL;
> +                       dev_err_probe(dev, ret,
> +                                     "failed to link to %s\n", data->name);
> +                       pm_genpd_remove(&domain->genpd);
> +                       dev_pm_domain_detach(domain->power_dev, true);
> +                       goto cleanup_pds;
> +               }
> +
>                 /*
>                  * We use runtime PM to trigger power on/off of the upstream GPC
>                  * domain, as a strict hierarchical parent/child power domain
> @@ -324,6 +338,7 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
>         of_genpd_del_provider(dev->of_node);
>  cleanup_pds:
>         for (i--; i >= 0; i--) {
> +               device_link_remove(dev, bc->domains[i].power_dev);
>                 pm_genpd_remove(&bc->domains[i].genpd);
>                 dev_pm_domain_detach(bc->domains[i].power_dev, true);
>         }
> @@ -343,6 +358,7 @@ static void imx8m_blk_ctrl_remove(struct platform_device *pdev)
>         for (i = 0; bc->onecell_data.num_domains; i++) {
>                 struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
>
> +               device_link_remove(&pdev->dev, domain->power_dev);
>                 pm_genpd_remove(&domain->genpd);
>                 dev_pm_domain_detach(domain->power_dev, true);
>         }
> --
> 2.34.1
>
Vitor Soares June 25, 2024, 7:32 a.m. UTC | #7
On Fri, 2024-05-10 at 11:34 +0200, Ulf Hansson wrote:
> On Thu, 18 Apr 2024 at 17:52, Vitor Soares <ivitro@gmail.com> wrote:
> > 
> > From: Vitor Soares <vitor.soares@toradex.com>
> > 
> > During the probe, the genpd power_dev is added to the dpm_list after
> > blk_ctrl due to its parent/child relationship. Making the blk_ctrl
> > suspend after and resume before the genpd power_dev.
> > 
> > As a consequence, the system hangs when resuming the VPU due to the
> > power domain dependency.
> > 
> > To ensure the proper suspend/resume order, add a device link betweem
> > blk_ctrl and genpd power_dev. It guarantees genpd power_dev is suspended
> > after and resumed before blk-ctrl.
> 
> Before discussing $subject patch, would you mind explaining to me why
> imx8m-blk-ctrl needs to use the ->suspend() callback at all?
> 
> Looking closer at that code (imx8m_blk_ctrl_suspend()), it calls
> pm_runtime_get_sync() for devices to power on "everything". Why isn't
> that managed by the consumer drivers (on a case by case basis) that
> are managing the devices that are attached to the genpds instead?
> 
> Kind regards
> Uffe
> 

Hi Lucas, you know the driver architecture better than I do. Would you mind
addressing Ulf concerns?


In addition to that, I would say that given that this is a bug fix, it would be
nice to have it merged. Having a buggy driver in the kernel is not solving this
kind of architectural question.


Best regards,
Vitor Soares

> > 
> > Cc: <stable@vger.kernel.org>
> > Closes:
> > https://lore.kernel.org/all/fccbb040330a706a4f7b34875db1d896a0bf81c8.camel@gmail.com/
> > Link: https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/
> > Fixes: 2684ac05a8c4 ("soc: imx: add i.MX8M blk-ctrl driver")
> > Suggested-by: Lucas Stach <l.stach@pengutronix.de>
> > Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
> > ---
> > 
> > This is a new patch, but is a follow-up of:
> > https://lore.kernel.org/all/20240409085802.290439-1-ivitro@gmail.com/
> > 
> > As suggested by Lucas, we are addressing this PM issue in the imx8m-blk-ctrl
> > driver instead of in the imx8mm.dtsi.
> > 
> >  drivers/pmdomain/imx/imx8m-blk-ctrl.c | 16 ++++++++++++++++
> >  1 file changed, 16 insertions(+)
> > 
> > diff --git a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> > b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> > index ca942d7929c2..cd0d2296080d 100644
> > --- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> > +++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
> > @@ -283,6 +283,20 @@ static int imx8m_blk_ctrl_probe(struct platform_device
> > *pdev)
> >                         goto cleanup_pds;
> >                 }
> > 
> > +               /*
> > +                * Enforce suspend/resume ordering by making genpd power_dev
> > a
> > +                * provider of blk-ctrl. Genpd power_dev is suspended after
> > and
> > +                * resumed before blk-ctrl.
> > +                */
> > +               if (!device_link_add(dev, domain->power_dev,
> > DL_FLAG_STATELESS)) {
> > +                       ret = -EINVAL;
> > +                       dev_err_probe(dev, ret,
> > +                                     "failed to link to %s\n", data->name);
> > +                       pm_genpd_remove(&domain->genpd);
> > +                       dev_pm_domain_detach(domain->power_dev, true);
> > +                       goto cleanup_pds;
> > +               }
> > +
> >                 /*
> >                  * We use runtime PM to trigger power on/off of the upstream
> > GPC
> >                  * domain, as a strict hierarchical parent/child power
> > domain
> > @@ -324,6 +338,7 @@ static int imx8m_blk_ctrl_probe(struct platform_device
> > *pdev)
> >         of_genpd_del_provider(dev->of_node);
> >  cleanup_pds:
> >         for (i--; i >= 0; i--) {
> > +               device_link_remove(dev, bc->domains[i].power_dev);
> >                 pm_genpd_remove(&bc->domains[i].genpd);
> >                 dev_pm_domain_detach(bc->domains[i].power_dev, true);
> >         }
> > @@ -343,6 +358,7 @@ static void imx8m_blk_ctrl_remove(struct platform_device
> > *pdev)
> >         for (i = 0; bc->onecell_data.num_domains; i++) {
> >                 struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
> > 
> > +               device_link_remove(&pdev->dev, domain->power_dev);
> >                 pm_genpd_remove(&domain->genpd);
> >                 dev_pm_domain_detach(domain->power_dev, true);
> >         }
> > --
> > 2.34.1
> >
diff mbox series

Patch

diff --git a/drivers/pmdomain/imx/imx8m-blk-ctrl.c b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
index ca942d7929c2..cd0d2296080d 100644
--- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
+++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
@@ -283,6 +283,20 @@  static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
 			goto cleanup_pds;
 		}
 
+		/*
+		 * Enforce suspend/resume ordering by making genpd power_dev a
+		 * provider of blk-ctrl. Genpd power_dev is suspended after and
+		 * resumed before blk-ctrl.
+		 */
+		if (!device_link_add(dev, domain->power_dev, DL_FLAG_STATELESS)) {
+			ret = -EINVAL;
+			dev_err_probe(dev, ret,
+				      "failed to link to %s\n", data->name);
+			pm_genpd_remove(&domain->genpd);
+			dev_pm_domain_detach(domain->power_dev, true);
+			goto cleanup_pds;
+		}
+
 		/*
 		 * We use runtime PM to trigger power on/off of the upstream GPC
 		 * domain, as a strict hierarchical parent/child power domain
@@ -324,6 +338,7 @@  static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
 	of_genpd_del_provider(dev->of_node);
 cleanup_pds:
 	for (i--; i >= 0; i--) {
+		device_link_remove(dev, bc->domains[i].power_dev);
 		pm_genpd_remove(&bc->domains[i].genpd);
 		dev_pm_domain_detach(bc->domains[i].power_dev, true);
 	}
@@ -343,6 +358,7 @@  static void imx8m_blk_ctrl_remove(struct platform_device *pdev)
 	for (i = 0; bc->onecell_data.num_domains; i++) {
 		struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
 
+		device_link_remove(&pdev->dev, domain->power_dev);
 		pm_genpd_remove(&domain->genpd);
 		dev_pm_domain_detach(domain->power_dev, true);
 	}