On Thu, 18 Apr 2024 at 17:52, Vitor Soares <ivitro@xxxxxxxxx> wrote: > > From: Vitor Soares <vitor.soares@xxxxxxxxxxx> > > 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@xxxxxxxxxxxxxxx> > Closes: https://lore.kernel.org/all/fccbb040330a706a4f7b34875db1d896a0bf81c8.camel@xxxxxxxxx/ > Link: https://lore.kernel.org/all/20240409085802.290439-1-ivitro@xxxxxxxxx/ > Fixes: 2684ac05a8c4 ("soc: imx: add i.MX8M blk-ctrl driver") > Suggested-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > Signed-off-by: Vitor Soares <vitor.soares@xxxxxxxxxxx> > --- > > This is a new patch, but is a follow-up of: > https://lore.kernel.org/all/20240409085802.290439-1-ivitro@xxxxxxxxx/ > > 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 >
