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[209.85.222.49]) by smtp.gmail.com with ESMTPSA id e21sm2074743uan.1.2020.03.17.14.38.50 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Mar 2020 14:38:51 -0700 (PDT) Received: by mail-ua1-f49.google.com with SMTP id q24so3770565ual.10 for ; Tue, 17 Mar 2020 14:38:50 -0700 (PDT) X-Received: by 2002:ab0:2881:: with SMTP id s1mr880973uap.8.1584481130400; Tue, 17 Mar 2020 14:38:50 -0700 (PDT) MIME-Version: 1.0 References: <1584356720-24411-1-git-send-email-kalyan_t@codeaurora.org> In-Reply-To: <1584356720-24411-1-git-send-email-kalyan_t@codeaurora.org> From: Doug Anderson Date: Tue, 17 Mar 2020 14:38:39 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] drm/msm/dpu: ensure device suspend happens during PM sleep To: Kalyan Thota Cc: dri-devel , linux-arm-msm , freedreno , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , LKML , Rob Clark , Sean Paul , "Kristian H. Kristensen" , Jeykumar Sankaran , travitej@codeaurora.org, Stephen Boyd Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, Mar 16, 2020 at 4:06 AM Kalyan Thota wrote: > > "The PM core always increments the runtime usage counter > before calling the ->suspend() callback and decrements it > after calling the ->resume() callback" > > DPU and DSI are managed as runtime devices. When > suspend is triggered, PM core adds a refcount on all the > devices and calls device suspend, since usage count is > already incremented, runtime suspend was not getting called > and it kept the clocks on which resulted in target not > entering into XO shutdown. > > Add changes to manage runtime devices during pm sleep. > > Signed-off-by: Kalyan Thota > --- > drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 41 +++++++++++++++++++++++++++++++++ > drivers/gpu/drm/msm/dsi/dsi.c | 7 ++++++ > drivers/gpu/drm/msm/msm_drv.c | 14 +++++++++++ > drivers/gpu/drm/msm/msm_kms.h | 2 ++ > 4 files changed, 64 insertions(+) > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c > index cb08faf..6e103d5 100644 > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c > @@ -26,6 +26,7 @@ > #include "dpu_encoder.h" > #include "dpu_plane.h" > #include "dpu_crtc.h" > +#include "dsi.h" > > #define CREATE_TRACE_POINTS > #include "dpu_trace.h" > @@ -250,6 +251,37 @@ static void dpu_kms_disable_commit(struct msm_kms *kms) > pm_runtime_put_sync(&dpu_kms->pdev->dev); > } > > +static void _dpu_kms_disable_dpu(struct msm_kms *kms) > +{ > + struct drm_device *dev; > + struct msm_drm_private *priv; > + struct dpu_kms *dpu_kms; > + int i = 0; > + struct msm_dsi *dsi; > + > + dpu_kms = to_dpu_kms(kms); > + dev = dpu_kms->dev; > + if (!dev) { > + DPU_ERROR("invalid device\n"); > + return; > + } > + > + priv = dev->dev_private; > + if (!priv) { > + DPU_ERROR("invalid private data\n"); > + return; > + } > + > + dpu_kms_disable_commit(kms); > + > + for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) { > + if (!priv->dsi[i]) > + continue; > + dsi = priv->dsi[i]; > + pm_runtime_put_sync(&dsi->pdev->dev); > + } > +} > + > static ktime_t dpu_kms_vsync_time(struct msm_kms *kms, struct drm_crtc *crtc) > { > struct drm_encoder *encoder; > @@ -683,6 +715,7 @@ static void dpu_irq_uninstall(struct msm_kms *kms) > #ifdef CONFIG_DEBUG_FS > .debugfs_init = dpu_kms_debugfs_init, > #endif > + .disable_dpu = _dpu_kms_disable_dpu, > }; > > static void _dpu_kms_mmu_destroy(struct dpu_kms *dpu_kms) > @@ -1053,7 +1086,15 @@ static int __maybe_unused dpu_runtime_resume(struct device *dev) > return rc; > } > > + > +static int __maybe_unused dpu_pm_suspend_late(struct device *dev) > +{ > + pm_runtime_get_noresume(dev); > + return 0; > +} > + > static const struct dev_pm_ops dpu_pm_ops = { > + SET_LATE_SYSTEM_SLEEP_PM_OPS(dpu_pm_suspend_late, NULL) > SET_RUNTIME_PM_OPS(dpu_runtime_suspend, dpu_runtime_resume, NULL) > }; > > diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c > index 55ea4bc2..3d3740e 100644 > --- a/drivers/gpu/drm/msm/dsi/dsi.c > +++ b/drivers/gpu/drm/msm/dsi/dsi.c > @@ -154,12 +154,19 @@ static int dsi_dev_remove(struct platform_device *pdev) > return 0; > } > > +static int __maybe_unused dsi_pm_suspend_late(struct device *dev) > +{ > + pm_runtime_get_noresume(dev); > + return 0; > +} > + > static const struct of_device_id dt_match[] = { > { .compatible = "qcom,mdss-dsi-ctrl" }, > {} > }; > > static const struct dev_pm_ops dsi_pm_ops = { > + SET_LATE_SYSTEM_SLEEP_PM_OPS(dsi_pm_suspend_late, NULL) > SET_RUNTIME_PM_OPS(msm_dsi_runtime_suspend, msm_dsi_runtime_resume, NULL) > }; > > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c > index e4b750b..12ec1c6 100644 > --- a/drivers/gpu/drm/msm/msm_drv.c > +++ b/drivers/gpu/drm/msm/msm_drv.c > @@ -1038,6 +1038,7 @@ static int msm_pm_suspend(struct device *dev) > { > struct drm_device *ddev = dev_get_drvdata(dev); > struct msm_drm_private *priv = ddev->dev_private; > + struct msm_kms *kms = priv->kms; > > if (WARN_ON(priv->pm_state)) > drm_atomic_state_put(priv->pm_state); > @@ -1049,6 +1050,11 @@ static int msm_pm_suspend(struct device *dev) > return ret; > } > > + if (kms->funcs->disable_dpu) > + kms->funcs->disable_dpu(kms); > + > + pm_runtime_put_sync(dev); > + > return 0; > } > > @@ -1067,6 +1073,13 @@ static int msm_pm_resume(struct device *dev) > > return ret; > } > + > +static int msm_pm_suspend_late(struct device *dev) > +{ > + pm_runtime_get_noresume(dev); > + return 0; > +} > + > #endif > > #ifdef CONFIG_PM > @@ -1100,6 +1113,7 @@ static int msm_runtime_resume(struct device *dev) > #endif > > static const struct dev_pm_ops msm_pm_ops = { > + SET_LATE_SYSTEM_SLEEP_PM_OPS(msm_pm_suspend_late, NULL) > SET_SYSTEM_SLEEP_PM_OPS(msm_pm_suspend, msm_pm_resume) > SET_RUNTIME_PM_OPS(msm_runtime_suspend, msm_runtime_resume, NULL) > }; > diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h > index 1cbef6b..c73a89b 100644 > --- a/drivers/gpu/drm/msm/msm_kms.h > +++ b/drivers/gpu/drm/msm/msm_kms.h > @@ -126,6 +126,8 @@ struct msm_kms_funcs { > /* debugfs: */ > int (*debugfs_init)(struct msm_kms *kms, struct drm_minor *minor); > #endif > + void (*disable_dpu)(struct msm_kms *kms); > + I'm by no means an expert on any of this, but it seems awfully asymmetric to me and that feels like you're going to end up with bugs. * Is it possible that disable_dpu() will be called more than once during normal operation, like if the screen goes off? Will your counts be off then? * What happens if suspend is aborted partway through (by getting a wakeup even as you're suspending, for instance)? In such a case some of the normal suspend calls will be called but "suspend_late" won't be called. Does that mess up your counting? >From your description, it sure seems like this part of the runtime_pm.rst doc is relevant to you: > Namely, if a system suspend .prepare() callback returns a positive > number for a device, that indicates to the PM core that the device > appears to be runtime-suspended and its state is fine, so it may > be left in runtime suspend provided that all of its descendants > are also left in runtime suspend. Did I misunderstand and this isn't what you want? Looking a bit further, maybe the right thing is to use the "SMART_SUSPEND" flag? I'll also note that sometimes when people just want to be Runtime PM managed that I see this pattern: SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume) -Doug