On Fri, 2024-05-10 at 11:34 +0200, Ulf Hansson wrote: > 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 > 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@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 > >
