From: "Théo Lebrun" <theo.lebrun@bootlin.com> To: "Roger Quadros" <rogerq@kernel.org>, "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>, "Rob Herring" <robh+dt@kernel.org>, "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>, "Conor Dooley" <conor+dt@kernel.org>, "Peter Chen" <peter.chen@kernel.org>, "Pawel Laszczak" <pawell@cadence.com>, "Nishanth Menon" <nm@ti.com>, "Vignesh Raghavendra" <vigneshr@ti.com>, "Tero Kristo" <kristo@kernel.org>, "Vardhan, Vibhore" <vibhore@ti.com> Cc: linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "Grégory Clement" <gregory.clement@bootlin.com>, "Thomas Petazzoni" <thomas.petazzoni@bootlin.com> Subject: Re: [PATCH 3/6] usb: cdns3-ti: add suspend/resume procedures for J7200 Date: Fri, 17 Nov 2023 11:17:55 +0100 [thread overview] Message-ID: <CX10D9YX1O1C.30PF317AG065N@tleb-bootlin-xps13-01> (raw) In-Reply-To: <bdea68ad-7523-4738-8fa1-b670d81a6b93@kernel.org> Hello, On Thu Nov 16, 2023 at 10:44 PM CET, Roger Quadros wrote: > On 16/11/2023 20:56, Théo Lebrun wrote: > > On Thu Nov 16, 2023 at 1:40 PM CET, Roger Quadros wrote: > >> On 15/11/2023 17:02, Théo Lebrun wrote: > >>> On Wed Nov 15, 2023 at 12:37 PM CET, Roger Quadros wrote: > >>>> You might want to check suspend/resume ops in cdns3-plat and > >>>> do something similar here. > >>> > >>> I'm unsure what you are referring to specifically in cdns3-plat? > >> > >> What I meant is, calling pm_runtime_get/put() from system suspend/resume > >> hooks doesn't seem right. > >> > >> How about using something like pm_runtime_forbid(dev) on devices which > >> loose USB context on runtime suspend e.g. J7200. > >> So at probe we can get rid of the pm_runtime_get_sync() call. > > > > What is the goal of enabling PM runtime to then block (ie forbid) it in > > its enabled state until system suspend? > > If USB controller retains context on runtime_suspend on some platforms > then we don't want to forbid PM runtime. What's the point of runtime PM if nothing is done based on it? This is the current behavior of the driver. > > Thinking some more about it and having read parts of the genpd source, > > it's unclear to me why there even is some PM runtime calls in this > > driver. No runtime_suspend/runtime_resume callbacks are registered. > > Also, power-domains work as expected without any PM runtime calls. > > Probably it was required when the driver was introduced. I'm not seeing any behavior change in cdns3-ti since its addition in Oct 2019. > > The power domain is turned on when attached to a device > > (see genpd_dev_pm_attach). It gets turned off automatically at > > suspend_noirq (taking into account the many things that make genpd > > complex: multiple devices per PD, subdomains, flags to customise the > > behavior, etc.). Removing calls to PM runtime at probe keeps the driver > > working. > > > > So my new proposal would be: remove all all PM runtime calls from this > > driver. Anything wrong with this approach? > > Nothing wrong if we don't expect runtime_pm to work with this driver. > > > > > Only possible reason I see for having PM runtime in this wrapper driver > > would be cut the full power-domain when USB isn't used, with some PM > > runtime interaction with the children node. But that cannot work > > currently as we don't register a runtime_resume to init the hardware, > > so this cannot be the current expected behavior. > > > >> e.g. > >> > >> pm_runtime_set_active(dev); > >> pm_runtime_enable(dev); > >> if (cnds_ti->can_loose_context) > >> pm_runtime_forbid(dev); > >> > >> pm_runtime_set_autosuspend_delay(dev, CNDS_TI_AUTOSUSPEND_DELAY); /* could be 20ms? */ > > > > Why mention autosuspend in this driver? This will turn the device off in > > CNDS_TI_AUTOSUSPEND_DELAY then nothing enables it back using > > pm_runtime_get. We have nothing to reconfigure the device, ie no > > runtime_resume, so we must not go into runtime suspend. > > It would be enabled/disabled based on when the child "cdns3,usb" > does runtime_resume/suspend. Why care about being enabled or disabled if we don't do anything based on that? Children does do runtime PM stuff but I don't understand how that could influence us. Regards, -- Théo Lebrun, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
WARNING: multiple messages have this Message-ID (diff)
From: "Théo Lebrun" <theo.lebrun@bootlin.com> To: "Roger Quadros" <rogerq@kernel.org>, "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>, "Rob Herring" <robh+dt@kernel.org>, "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>, "Conor Dooley" <conor+dt@kernel.org>, "Peter Chen" <peter.chen@kernel.org>, "Pawel Laszczak" <pawell@cadence.com>, "Nishanth Menon" <nm@ti.com>, "Vignesh Raghavendra" <vigneshr@ti.com>, "Tero Kristo" <kristo@kernel.org>, "Vardhan, Vibhore" <vibhore@ti.com> Cc: linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "Grégory Clement" <gregory.clement@bootlin.com>, "Thomas Petazzoni" <thomas.petazzoni@bootlin.com> Subject: Re: [PATCH 3/6] usb: cdns3-ti: add suspend/resume procedures for J7200 Date: Fri, 17 Nov 2023 11:17:55 +0100 [thread overview] Message-ID: <CX10D9YX1O1C.30PF317AG065N@tleb-bootlin-xps13-01> (raw) In-Reply-To: <bdea68ad-7523-4738-8fa1-b670d81a6b93@kernel.org> Hello, On Thu Nov 16, 2023 at 10:44 PM CET, Roger Quadros wrote: > On 16/11/2023 20:56, Théo Lebrun wrote: > > On Thu Nov 16, 2023 at 1:40 PM CET, Roger Quadros wrote: > >> On 15/11/2023 17:02, Théo Lebrun wrote: > >>> On Wed Nov 15, 2023 at 12:37 PM CET, Roger Quadros wrote: > >>>> You might want to check suspend/resume ops in cdns3-plat and > >>>> do something similar here. > >>> > >>> I'm unsure what you are referring to specifically in cdns3-plat? > >> > >> What I meant is, calling pm_runtime_get/put() from system suspend/resume > >> hooks doesn't seem right. > >> > >> How about using something like pm_runtime_forbid(dev) on devices which > >> loose USB context on runtime suspend e.g. J7200. > >> So at probe we can get rid of the pm_runtime_get_sync() call. > > > > What is the goal of enabling PM runtime to then block (ie forbid) it in > > its enabled state until system suspend? > > If USB controller retains context on runtime_suspend on some platforms > then we don't want to forbid PM runtime. What's the point of runtime PM if nothing is done based on it? This is the current behavior of the driver. > > Thinking some more about it and having read parts of the genpd source, > > it's unclear to me why there even is some PM runtime calls in this > > driver. No runtime_suspend/runtime_resume callbacks are registered. > > Also, power-domains work as expected without any PM runtime calls. > > Probably it was required when the driver was introduced. I'm not seeing any behavior change in cdns3-ti since its addition in Oct 2019. > > The power domain is turned on when attached to a device > > (see genpd_dev_pm_attach). It gets turned off automatically at > > suspend_noirq (taking into account the many things that make genpd > > complex: multiple devices per PD, subdomains, flags to customise the > > behavior, etc.). Removing calls to PM runtime at probe keeps the driver > > working. > > > > So my new proposal would be: remove all all PM runtime calls from this > > driver. Anything wrong with this approach? > > Nothing wrong if we don't expect runtime_pm to work with this driver. > > > > > Only possible reason I see for having PM runtime in this wrapper driver > > would be cut the full power-domain when USB isn't used, with some PM > > runtime interaction with the children node. But that cannot work > > currently as we don't register a runtime_resume to init the hardware, > > so this cannot be the current expected behavior. > > > >> e.g. > >> > >> pm_runtime_set_active(dev); > >> pm_runtime_enable(dev); > >> if (cnds_ti->can_loose_context) > >> pm_runtime_forbid(dev); > >> > >> pm_runtime_set_autosuspend_delay(dev, CNDS_TI_AUTOSUSPEND_DELAY); /* could be 20ms? */ > > > > Why mention autosuspend in this driver? This will turn the device off in > > CNDS_TI_AUTOSUSPEND_DELAY then nothing enables it back using > > pm_runtime_get. We have nothing to reconfigure the device, ie no > > runtime_resume, so we must not go into runtime suspend. > > It would be enabled/disabled based on when the child "cdns3,usb" > does runtime_resume/suspend. Why care about being enabled or disabled if we don't do anything based on that? Children does do runtime PM stuff but I don't understand how that could influence us. Regards, -- Théo Lebrun, Bootlin Embedded Linux and Kernel engineering https://bootlin.com _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-11-17 10:18 UTC|newest] Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-11-13 14:26 [PATCH 0/6] usb: cdns: fix suspend on J7200 by assuming reset on resume Théo Lebrun 2023-11-13 14:26 ` Théo Lebrun 2023-11-13 14:26 ` [PATCH 1/6] dt-bindings: usb: ti,j721e-usb: add ti,j7200-usb compatible Théo Lebrun 2023-11-13 14:26 ` Théo Lebrun 2023-11-13 19:58 ` Conor Dooley 2023-11-13 19:58 ` Conor Dooley 2023-11-13 14:26 ` [PATCH 2/6] usb: cdns3-ti: move reg writes from probe into an init_hw helper Théo Lebrun 2023-11-13 14:26 ` Théo Lebrun 2023-11-15 11:33 ` Roger Quadros 2023-11-15 11:33 ` Roger Quadros 2023-11-15 14:23 ` Théo Lebrun 2023-11-15 14:23 ` Théo Lebrun 2023-11-16 12:00 ` Roger Quadros 2023-11-16 12:00 ` Roger Quadros 2023-11-13 14:26 ` [PATCH 3/6] usb: cdns3-ti: add suspend/resume procedures for J7200 Théo Lebrun 2023-11-13 14:26 ` Théo Lebrun 2023-11-13 15:39 ` Gregory CLEMENT 2023-11-13 15:39 ` Gregory CLEMENT 2023-11-14 11:13 ` Théo Lebrun 2023-11-14 11:13 ` Théo Lebrun 2023-11-15 11:37 ` Roger Quadros 2023-11-15 11:37 ` Roger Quadros 2023-11-15 15:02 ` Théo Lebrun 2023-11-15 15:02 ` Théo Lebrun 2023-11-16 12:40 ` Roger Quadros 2023-11-16 12:40 ` Roger Quadros 2023-11-16 18:56 ` Théo Lebrun 2023-11-16 18:56 ` Théo Lebrun 2023-11-16 21:44 ` Roger Quadros 2023-11-16 21:44 ` Roger Quadros 2023-11-17 10:17 ` Théo Lebrun [this message] 2023-11-17 10:17 ` Théo Lebrun 2023-11-17 11:51 ` Roger Quadros 2023-11-17 11:51 ` Roger Quadros 2023-11-17 14:20 ` Théo Lebrun 2023-11-17 14:20 ` Théo Lebrun 2023-11-18 10:41 ` Roger Quadros 2023-11-18 10:41 ` Roger Quadros 2023-11-22 22:23 ` Kevin Hilman 2023-11-22 22:23 ` Kevin Hilman 2023-11-23 9:51 ` Théo Lebrun 2023-11-23 9:51 ` Théo Lebrun 2023-11-26 22:36 ` Kevin Hilman 2023-11-26 22:36 ` Kevin Hilman 2023-11-27 13:25 ` Théo Lebrun 2023-11-27 13:25 ` Théo Lebrun 2023-12-12 18:26 ` Kevin Hilman 2023-12-12 18:26 ` Kevin Hilman 2023-12-12 19:31 ` Alan Stern 2023-12-12 19:31 ` Alan Stern 2023-11-13 14:26 ` [PATCH 4/6] usb: cdns3: support power-off of controller when in host role Théo Lebrun 2023-11-13 14:26 ` Théo Lebrun 2023-11-14 8:38 ` Peter Chen 2023-11-14 8:38 ` Peter Chen 2023-11-14 11:10 ` Théo Lebrun 2023-11-14 11:10 ` Théo Lebrun 2023-11-17 3:38 ` Peter Chen 2023-11-17 3:38 ` Peter Chen 2023-11-17 9:58 ` Théo Lebrun 2023-11-17 9:58 ` Théo Lebrun 2023-11-20 5:44 ` Peter Chen 2023-11-20 5:44 ` Peter Chen 2023-11-13 14:27 ` [PATCH 5/6] usb: cdns3-ti: notify cdns core that hardware resets across suspend on J7200 Théo Lebrun 2023-11-13 14:27 ` Théo Lebrun 2023-11-13 14:27 ` [PATCH 6/6] arm64: dts: ti: k3-j7200: use J7200-specific USB compatible Théo Lebrun 2023-11-13 14:27 ` Théo Lebrun 2023-11-14 10:01 ` Gregory CLEMENT 2023-11-14 10:01 ` Gregory CLEMENT 2023-11-14 11:14 ` Théo Lebrun 2023-11-14 11:14 ` Théo Lebrun
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=CX10D9YX1O1C.30PF317AG065N@tleb-bootlin-xps13-01 \ --to=theo.lebrun@bootlin.com \ --cc=conor+dt@kernel.org \ --cc=devicetree@vger.kernel.org \ --cc=gregkh@linuxfoundation.org \ --cc=gregory.clement@bootlin.com \ --cc=kristo@kernel.org \ --cc=krzysztof.kozlowski+dt@linaro.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-usb@vger.kernel.org \ --cc=nm@ti.com \ --cc=pawell@cadence.com \ --cc=peter.chen@kernel.org \ --cc=robh+dt@kernel.org \ --cc=rogerq@kernel.org \ --cc=thomas.petazzoni@bootlin.com \ --cc=vibhore@ti.com \ --cc=vigneshr@ti.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.