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

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@g... 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