| Message ID | 1522083800-30100-9-git-send-email-ayan.halder@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Mar 26, 2018 at 06:03:20PM +0100, Ayan Kumar Halder wrote: > malidp_pm_suspend_late checks if the runtime status is not suspended > and if so, invokes malidp_runtime_pm_suspend which disables the > display engine/core interrupts and the clocks. It sets the runtime status > as suspended. Subsequently, malidp_pm_resume_early will invoke > malidp_runtime_pm_resume which enables the clocks and the interrupts > (previously disabled) and sets the runtime status as active. > > Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> > Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda Why exactly do you need late/early hooks? If you have dependencies with other devices, pls consider adding device_links instead. This here shouldn't be necessary. -Daniel > --- > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c > index bd44a6d..f6124d8 100644 > --- a/drivers/gpu/drm/arm/malidp_drv.c > +++ b/drivers/gpu/drm/arm/malidp_drv.c > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) > return 0; > } > > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) > +{ > + if (!pm_runtime_status_suspended(dev)) { > + malidp_runtime_pm_suspend(dev); > + pm_runtime_set_suspended(dev); > + } > + return 0; > +} > + > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) > +{ > + malidp_runtime_pm_resume(dev); > + pm_runtime_set_active(dev); > + return 0; > +} > + > static const struct dev_pm_ops malidp_pm_ops = { > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) > }; > > -- > 2.7.4 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Tue, Mar 27, 2018 at 10:29:03AM +0200, Daniel Vetter wrote: > On Mon, Mar 26, 2018 at 06:03:20PM +0100, Ayan Kumar Halder wrote: > > malidp_pm_suspend_late checks if the runtime status is not suspended > > and if so, invokes malidp_runtime_pm_suspend which disables the > > display engine/core interrupts and the clocks. It sets the runtime status > > as suspended. Subsequently, malidp_pm_resume_early will invoke > > malidp_runtime_pm_resume which enables the clocks and the interrupts > > (previously disabled) and sets the runtime status as active. > > > > Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> > > Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda > > Why exactly do you need late/early hooks? If you have dependencies with > other devices, pls consider adding device_links instead. This here > shouldn't be necessary. > -Daniel We need to late/early hooks to disable malidp interrupts and the clocks. > > --- > > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ > > 1 file changed, 17 insertions(+) > > > > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c > > index bd44a6d..f6124d8 100644 > > --- a/drivers/gpu/drm/arm/malidp_drv.c > > +++ b/drivers/gpu/drm/arm/malidp_drv.c > > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) > > return 0; > > } > > > > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) > > +{ > > + if (!pm_runtime_status_suspended(dev)) { > > + malidp_runtime_pm_suspend(dev); > > + pm_runtime_set_suspended(dev); > > + } > > + return 0; > > +} > > + > > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) > > +{ > > + malidp_runtime_pm_resume(dev); > > + pm_runtime_set_active(dev); > > + return 0; > > +} > > + > > static const struct dev_pm_ops malidp_pm_ops = { > > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ > > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ > > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) > > }; > > > > -- > > 2.7.4 > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
On Tue, Mar 27, 2018 at 11:59 AM, Ayan Halder <ayan.halder@arm.com> wrote: > On Tue, Mar 27, 2018 at 10:29:03AM +0200, Daniel Vetter wrote: >> On Mon, Mar 26, 2018 at 06:03:20PM +0100, Ayan Kumar Halder wrote: >> > malidp_pm_suspend_late checks if the runtime status is not suspended >> > and if so, invokes malidp_runtime_pm_suspend which disables the >> > display engine/core interrupts and the clocks. It sets the runtime status >> > as suspended. Subsequently, malidp_pm_resume_early will invoke >> > malidp_runtime_pm_resume which enables the clocks and the interrupts >> > (previously disabled) and sets the runtime status as active. >> > >> > Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> >> > Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda >> >> Why exactly do you need late/early hooks? If you have dependencies with >> other devices, pls consider adding device_links instead. This here >> shouldn't be necessary. >> -Daniel > We need to late/early hooks to disable malidp interrupts and the > clocks. Yes, but why this ordering constraint? Why can't you just disable the interrupts/clocks in the normal suspend code. I see that the patch does this, I want to understand why it does it. -Daniel >> > --- >> > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ >> > 1 file changed, 17 insertions(+) >> > >> > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c >> > index bd44a6d..f6124d8 100644 >> > --- a/drivers/gpu/drm/arm/malidp_drv.c >> > +++ b/drivers/gpu/drm/arm/malidp_drv.c >> > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) >> > return 0; >> > } >> > >> > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) >> > +{ >> > + if (!pm_runtime_status_suspended(dev)) { >> > + malidp_runtime_pm_suspend(dev); >> > + pm_runtime_set_suspended(dev); >> > + } >> > + return 0; >> > +} >> > + >> > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) >> > +{ >> > + malidp_runtime_pm_resume(dev); >> > + pm_runtime_set_active(dev); >> > + return 0; >> > +} >> > + >> > static const struct dev_pm_ops malidp_pm_ops = { >> > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ >> > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ >> > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) >> > }; >> > >> > -- >> > 2.7.4 >> > >> > _______________________________________________ >> > dri-devel mailing list >> > dri-devel@lists.freedesktop.org >> > https://lists.freedesktop.org/mailman/listinfo/dri-devel >> >> -- >> Daniel Vetter >> Software Engineer, Intel Corporation >> http://blog.ffwll.ch >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Tue, Mar 27, 2018 at 01:09:36PM +0200, Daniel Vetter wrote: > On Tue, Mar 27, 2018 at 11:59 AM, Ayan Halder <ayan.halder@arm.com> wrote: > > On Tue, Mar 27, 2018 at 10:29:03AM +0200, Daniel Vetter wrote: > >> On Mon, Mar 26, 2018 at 06:03:20PM +0100, Ayan Kumar Halder wrote: > >> > malidp_pm_suspend_late checks if the runtime status is not suspended > >> > and if so, invokes malidp_runtime_pm_suspend which disables the > >> > display engine/core interrupts and the clocks. It sets the runtime status > >> > as suspended. Subsequently, malidp_pm_resume_early will invoke > >> > malidp_runtime_pm_resume which enables the clocks and the interrupts > >> > (previously disabled) and sets the runtime status as active. > >> > > >> > Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> > >> > Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda > >> > >> Why exactly do you need late/early hooks? If you have dependencies with > >> other devices, pls consider adding device_links instead. This here > >> shouldn't be necessary. > >> -Daniel > > We need to late/early hooks to disable malidp interrupts and the > > clocks. > > Yes, but why this ordering constraint? Why can't you just disable the > interrupts/clocks in the normal suspend code. I see that the patch > does this, I want to understand why it does it. > -Daniel Apologies for my delayed response on this. With reference to https://lwn.net/Articles/505683/ :- 1. "suspend() should leave the device in a quiescent state." We invoke drm_mode_config_helper_suspend() which deactivates the crtc. I understand that this is the quiescent state. 2. "suspend_late() can often be the same as runtime_suspend()." We invoke runtime suspend/resume calls in late/early hooks. > >> > --- > >> > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ > >> > 1 file changed, 17 insertions(+) > >> > > >> > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c > >> > index bd44a6d..f6124d8 100644 > >> > --- a/drivers/gpu/drm/arm/malidp_drv.c > >> > +++ b/drivers/gpu/drm/arm/malidp_drv.c > >> > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) > >> > return 0; > >> > } > >> > > >> > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) > >> > +{ > >> > + if (!pm_runtime_status_suspended(dev)) { > >> > + malidp_runtime_pm_suspend(dev); > >> > + pm_runtime_set_suspended(dev); > >> > + } > >> > + return 0; > >> > +} > >> > + > >> > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) > >> > +{ > >> > + malidp_runtime_pm_resume(dev); > >> > + pm_runtime_set_active(dev); > >> > + return 0; > >> > +} > >> > + > >> > static const struct dev_pm_ops malidp_pm_ops = { > >> > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ > >> > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ > >> > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) > >> > }; > >> > > >> > -- > >> > 2.7.4 > >> > > >> > _______________________________________________ > >> > dri-devel mailing list > >> > dri-devel@lists.freedesktop.org > >> > https://lists.freedesktop.org/mailman/listinfo/dri-devel > >> > >> -- > >> Daniel Vetter > >> Software Engineer, Intel Corporation > >> http://blog.ffwll.ch > >> _______________________________________________ > >> dri-devel mailing list > >> dri-devel@lists.freedesktop.org > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > -- > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Fri, Apr 06, 2018 at 08:02:16PM +0100, Ayan Halder wrote: > On Tue, Mar 27, 2018 at 01:09:36PM +0200, Daniel Vetter wrote: > > On Tue, Mar 27, 2018 at 11:59 AM, Ayan Halder <ayan.halder@arm.com> wrote: > > > On Tue, Mar 27, 2018 at 10:29:03AM +0200, Daniel Vetter wrote: > > >> On Mon, Mar 26, 2018 at 06:03:20PM +0100, Ayan Kumar Halder wrote: > > >> > malidp_pm_suspend_late checks if the runtime status is not suspended > > >> > and if so, invokes malidp_runtime_pm_suspend which disables the > > >> > display engine/core interrupts and the clocks. It sets the runtime status > > >> > as suspended. Subsequently, malidp_pm_resume_early will invoke > > >> > malidp_runtime_pm_resume which enables the clocks and the interrupts > > >> > (previously disabled) and sets the runtime status as active. > > >> > > > >> > Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> > > >> > Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda > > >> > > >> Why exactly do you need late/early hooks? If you have dependencies with > > >> other devices, pls consider adding device_links instead. This here > > >> shouldn't be necessary. > > >> -Daniel > > > We need to late/early hooks to disable malidp interrupts and the > > > clocks. > > > > Yes, but why this ordering constraint? Why can't you just disable the > > interrupts/clocks in the normal suspend code. I see that the patch > > does this, I want to understand why it does it. > > -Daniel > Apologies for my delayed response on this. > > With reference to https://lwn.net/Articles/505683/ :- > 1. "suspend() should leave the device in a quiescent state." We invoke > drm_mode_config_helper_suspend() which deactivates the crtc. I > understand that this is the quiescent state. > > 2. "suspend_late() can often be the same as runtime_suspend()." We > invoke runtime suspend/resume calls in late/early hooks. This article is from 2012. That's not really recommended best practices anymore. device_links have only been added a few years ago, so ofc an article from 2012 can't tell you that you should use those instead :-) That's why I brought this up, we have much better ways to handle device dependencies now. Also, you still haven't explained what exactly the dependency is. -Daniel > > > >> > --- > > >> > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ > > >> > 1 file changed, 17 insertions(+) > > >> > > > >> > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c > > >> > index bd44a6d..f6124d8 100644 > > >> > --- a/drivers/gpu/drm/arm/malidp_drv.c > > >> > +++ b/drivers/gpu/drm/arm/malidp_drv.c > > >> > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) > > >> > return 0; > > >> > } > > >> > > > >> > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) > > >> > +{ > > >> > + if (!pm_runtime_status_suspended(dev)) { > > >> > + malidp_runtime_pm_suspend(dev); > > >> > + pm_runtime_set_suspended(dev); > > >> > + } > > >> > + return 0; > > >> > +} > > >> > + > > >> > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) > > >> > +{ > > >> > + malidp_runtime_pm_resume(dev); > > >> > + pm_runtime_set_active(dev); > > >> > + return 0; > > >> > +} > > >> > + > > >> > static const struct dev_pm_ops malidp_pm_ops = { > > >> > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ > > >> > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ > > >> > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) > > >> > }; > > >> > > > >> > -- > > >> > 2.7.4 > > >> > > > >> > _______________________________________________ > > >> > dri-devel mailing list > > >> > dri-devel@lists.freedesktop.org > > >> > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > >> > > >> -- > > >> Daniel Vetter > > >> Software Engineer, Intel Corporation > > >> http://blog.ffwll.ch > > >> _______________________________________________ > > >> dri-devel mailing list > > >> dri-devel@lists.freedesktop.org > > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. > > > _______________________________________________ > > > dri-devel mailing list > > > dri-devel@lists.freedesktop.org > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
Hi Daniel, On Mon, Apr 09, 2018 at 10:23:37AM +0200, Daniel Vetter wrote: >On Fri, Apr 06, 2018 at 08:02:16PM +0100, Ayan Halder wrote: >> On Tue, Mar 27, 2018 at 01:09:36PM +0200, Daniel Vetter wrote: >> > On Tue, Mar 27, 2018 at 11:59 AM, Ayan Halder <ayan.halder@arm.com> wrote: >> > > On Tue, Mar 27, 2018 at 10:29:03AM +0200, Daniel Vetter wrote: >> > >> On Mon, Mar 26, 2018 at 06:03:20PM +0100, Ayan Kumar Halder wrote: >> > >> > malidp_pm_suspend_late checks if the runtime status is not suspended >> > >> > and if so, invokes malidp_runtime_pm_suspend which disables the >> > >> > display engine/core interrupts and the clocks. It sets the runtime status >> > >> > as suspended. Subsequently, malidp_pm_resume_early will invoke >> > >> > malidp_runtime_pm_resume which enables the clocks and the interrupts >> > >> > (previously disabled) and sets the runtime status as active. >> > >> > >> > >> > Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> >> > >> > Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda >> > >> >> > >> Why exactly do you need late/early hooks? If you have dependencies with >> > >> other devices, pls consider adding device_links instead. This here >> > >> shouldn't be necessary. >> > >> -Daniel >> > > We need to late/early hooks to disable malidp interrupts and the >> > > clocks. >> > >> > Yes, but why this ordering constraint? Why can't you just disable the >> > interrupts/clocks in the normal suspend code. I see that the patch >> > does this, I want to understand why it does it. >> > -Daniel >> Apologies for my delayed response on this. >> >> With reference to https://lwn.net/Articles/505683/ :- >> 1. "suspend() should leave the device in a quiescent state." We invoke >> drm_mode_config_helper_suspend() which deactivates the crtc. I >> understand that this is the quiescent state. >> >> 2. "suspend_late() can often be the same as runtime_suspend()." We >> invoke runtime suspend/resume calls in late/early hooks. > >This article is from 2012. That's not really recommended best practices >anymore. device_links have only been added a few years ago, so ofc an >article from 2012 can't tell you that you should use those instead :-) > >That's why I brought this up, we have much better ways to handle device >dependencies now. > We aren't trying to manage any device dependencies here, I don't know where that idea came from? The kernel-doc on drm-next this afternoon says effectively the same thing: * @suspend: Executed before putting the system into a sleep state in which the * contents of main memory are preserved. The exact action to perform * depends on the device's subsystem (PM domain, device type, class or bus * type), but generally the device must be quiescent after subsystem-level * @suspend() has returned, so that it doesn't do any I/O or DMA. * Subsystem-level @suspend() is executed for all devices after invoking * subsystem-level @prepare() for all of them. (i.e. suspend() makes the device quiescent). * @suspend_late: Continue operations started by @suspend(). For a number of * devices @suspend_late() may point to the same callback routine as the * runtime suspend callback. (suggests suspend_late() be assigned to the same function as runtime suspend). As for why, my understanding is like so: For ->suspend(), we use the DRM helper, which disables the CRTC. Normally disabling the CRTC would be enough to also invoke our pm_runtime callback to do the final clock disable etc., however when a system suspend is in-progress, the core forcibly takes a runtime reference on all devices - preventing any pm_runtime paths from running. This means that after the CRTC is disabled in ->suspend(), our normal pm_runtime path will not be invoked, and so the things done in malidp_runtime_pm_suspend() will never happen. We were just following the advice in the kernel-doc to deal with this. The alternative would be to call malidp_runtime_pm_{suspend,resume} from the "not late" hooks, but I'd ask why? >Also, you still haven't explained what exactly the dependency is. Because there isn't one :-) Thanks, -Brian >-Daniel > >> >> > >> > --- >> > >> > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ >> > >> > 1 file changed, 17 insertions(+) >> > >> > >> > >> > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c >> > >> > index bd44a6d..f6124d8 100644 >> > >> > --- a/drivers/gpu/drm/arm/malidp_drv.c >> > >> > +++ b/drivers/gpu/drm/arm/malidp_drv.c >> > >> > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) >> > >> > return 0; >> > >> > } >> > >> > >> > >> > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) >> > >> > +{ >> > >> > + if (!pm_runtime_status_suspended(dev)) { >> > >> > + malidp_runtime_pm_suspend(dev); >> > >> > + pm_runtime_set_suspended(dev); >> > >> > + } >> > >> > + return 0; >> > >> > +} >> > >> > + >> > >> > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) >> > >> > +{ >> > >> > + malidp_runtime_pm_resume(dev); >> > >> > + pm_runtime_set_active(dev); >> > >> > + return 0; >> > >> > +} >> > >> > + >> > >> > static const struct dev_pm_ops malidp_pm_ops = { >> > >> > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ >> > >> > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ >> > >> > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) >> > >> > }; >> > >> > >> > >> > -- >> > >> > 2.7.4 >> > >> > >> > >> > _______________________________________________ >> > >> > dri-devel mailing list >> > >> > dri-devel@lists.freedesktop.org >> > >> > https://lists.freedesktop.org/mailman/listinfo/dri-devel >> > >> >> > >> -- >> > >> Daniel Vetter >> > >> Software Engineer, Intel Corporation >> > >> http://blog.ffwll.ch >> > >> _______________________________________________ >> > >> dri-devel mailing list >> > >> dri-devel@lists.freedesktop.org >> > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel >> > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. >> > > _______________________________________________ >> > > dri-devel mailing list >> > > dri-devel@lists.freedesktop.org >> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel >> > >> > >> > >> > -- >> > Daniel Vetter >> > Software Engineer, Intel Corporation >> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch > >-- >Daniel Vetter >Software Engineer, Intel Corporation >http://blog.ffwll.ch
On Mon, Apr 09, 2018 at 05:15:08PM +0100, Brian Starkey wrote: > Hi Daniel, > > On Mon, Apr 09, 2018 at 10:23:37AM +0200, Daniel Vetter wrote: > > On Fri, Apr 06, 2018 at 08:02:16PM +0100, Ayan Halder wrote: > > > On Tue, Mar 27, 2018 at 01:09:36PM +0200, Daniel Vetter wrote: > > > > On Tue, Mar 27, 2018 at 11:59 AM, Ayan Halder <ayan.halder@arm.com> wrote: > > > > > On Tue, Mar 27, 2018 at 10:29:03AM +0200, Daniel Vetter wrote: > > > > >> On Mon, Mar 26, 2018 at 06:03:20PM +0100, Ayan Kumar Halder wrote: > > > > >> > malidp_pm_suspend_late checks if the runtime status is not suspended > > > > >> > and if so, invokes malidp_runtime_pm_suspend which disables the > > > > >> > display engine/core interrupts and the clocks. It sets the runtime status > > > > >> > as suspended. Subsequently, malidp_pm_resume_early will invoke > > > > >> > malidp_runtime_pm_resume which enables the clocks and the interrupts > > > > >> > (previously disabled) and sets the runtime status as active. > > > > >> > > > > > >> > Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> > > > > >> > Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda > > > > >> > > > > >> Why exactly do you need late/early hooks? If you have dependencies with > > > > >> other devices, pls consider adding device_links instead. This here > > > > >> shouldn't be necessary. > > > > >> -Daniel > > > > > We need to late/early hooks to disable malidp interrupts and the > > > > > clocks. > > > > > > > > Yes, but why this ordering constraint? Why can't you just disable the > > > > interrupts/clocks in the normal suspend code. I see that the patch > > > > does this, I want to understand why it does it. > > > > -Daniel > > > Apologies for my delayed response on this. > > > > > > With reference to https://lwn.net/Articles/505683/ :- > > > 1. "suspend() should leave the device in a quiescent state." We invoke > > > drm_mode_config_helper_suspend() which deactivates the crtc. I > > > understand that this is the quiescent state. > > > > > > 2. "suspend_late() can often be the same as runtime_suspend()." We > > > invoke runtime suspend/resume calls in late/early hooks. > > > > This article is from 2012. That's not really recommended best practices > > anymore. device_links have only been added a few years ago, so ofc an > > article from 2012 can't tell you that you should use those instead :-) > > > > That's why I brought this up, we have much better ways to handle device > > dependencies now. > > > > We aren't trying to manage any device dependencies here, I don't know > where that idea came from? > > The kernel-doc on drm-next this afternoon says effectively the same > thing: > > * @suspend: Executed before putting the system into a sleep state in which the > * contents of main memory are preserved. The exact action to perform > * depends on the device's subsystem (PM domain, device type, class or bus > * type), but generally the device must be quiescent after subsystem-level > * @suspend() has returned, so that it doesn't do any I/O or DMA. > * Subsystem-level @suspend() is executed for all devices after invoking > * subsystem-level @prepare() for all of them. > > (i.e. suspend() makes the device quiescent). > > * @suspend_late: Continue operations started by @suspend(). For a number of > * devices @suspend_late() may point to the same callback routine as the > * runtime suspend callback. > > (suggests suspend_late() be assigned to the same function as runtime > suspend). > > As for why, my understanding is like so: > > For ->suspend(), we use the DRM helper, which disables the CRTC. > Normally disabling the CRTC would be enough to also invoke our > pm_runtime callback to do the final clock disable etc., however when a > system suspend is in-progress, the core forcibly takes a runtime > reference on all devices - preventing any pm_runtime paths from > running. I thought this was fixed. At least I remember we had to add some special calls to i915 to opt out of the "do runtime pm as part of suspend/resume" behaviour, since it doesn't match what we needed. See commit aae4518b3124b29f8dc81c829c704fd2df72e98b Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Date: Fri May 16 02:46:50 2014 +0200 PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily So I thought this stuff was supposed to work now. Adding Rafael Wyzocki, he's done plenty presentations recently about exactly this. > This means that after the CRTC is disabled in ->suspend(), our normal > pm_runtime path will not be invoked, and so the things done in > malidp_runtime_pm_suspend() will never happen. > > We were just following the advice in the kernel-doc to deal with this. > > The alternative would be to call malidp_runtime_pm_{suspend,resume} > from the "not late" hooks, but I'd ask why? > > > Also, you still haven't explained what exactly the dependency is. > > Because there isn't one :-) Hm, if there really isn't one, then I guess it's ok. But it's way too easy to screw this up, have an accidental depency on a different device. And then you try to fix this up. Having a suspend_late hook still smells fishy to me, but I might be out of the loop. -Daniel > > Thanks, > -Brian > > > -Daniel > > > > > > > > > >> > --- > > > > >> > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ > > > > >> > 1 file changed, 17 insertions(+) > > > > >> > > > > > >> > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c > > > > >> > index bd44a6d..f6124d8 100644 > > > > >> > --- a/drivers/gpu/drm/arm/malidp_drv.c > > > > >> > +++ b/drivers/gpu/drm/arm/malidp_drv.c > > > > >> > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) > > > > >> > return 0; > > > > >> > } > > > > >> > > > > > >> > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) > > > > >> > +{ > > > > >> > + if (!pm_runtime_status_suspended(dev)) { > > > > >> > + malidp_runtime_pm_suspend(dev); > > > > >> > + pm_runtime_set_suspended(dev); > > > > >> > + } > > > > >> > + return 0; > > > > >> > +} > > > > >> > + > > > > >> > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) > > > > >> > +{ > > > > >> > + malidp_runtime_pm_resume(dev); > > > > >> > + pm_runtime_set_active(dev); > > > > >> > + return 0; > > > > >> > +} > > > > >> > + > > > > >> > static const struct dev_pm_ops malidp_pm_ops = { > > > > >> > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ > > > > >> > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ > > > > >> > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) > > > > >> > }; > > > > >> > > > > > >> > -- > > > > >> > 2.7.4 > > > > >> > > > > > >> > _______________________________________________ > > > > >> > dri-devel mailing list > > > > >> > dri-devel@lists.freedesktop.org > > > > >> > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > >> > > > > >> -- > > > > >> Daniel Vetter > > > > >> Software Engineer, Intel Corporation > > > > >> http://blog.ffwll.ch > > > > >> _______________________________________________ > > > > >> dri-devel mailing list > > > > >> dri-devel@lists.freedesktop.org > > > > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. > > > > > _______________________________________________ > > > > > dri-devel mailing list > > > > > dri-devel@lists.freedesktop.org > > > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > > > > > > > > > > > > > -- > > > > Daniel Vetter > > > > Software Engineer, Intel Corporation > > > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch
Hi Daniel, On Fri, Apr 13, 2018 at 05:44:09PM +0200, Daniel Vetter wrote: >On Mon, Apr 09, 2018 at 05:15:08PM +0100, Brian Starkey wrote: >> Hi Daniel, >> >> On Mon, Apr 09, 2018 at 10:23:37AM +0200, Daniel Vetter wrote: >> > On Fri, Apr 06, 2018 at 08:02:16PM +0100, Ayan Halder wrote: >> > > On Tue, Mar 27, 2018 at 01:09:36PM +0200, Daniel Vetter wrote: >> > > > On Tue, Mar 27, 2018 at 11:59 AM, Ayan Halder <ayan.halder@arm.com> wrote: [snip] >> >> As for why, my understanding is like so: >> >> For ->suspend(), we use the DRM helper, which disables the CRTC. >> Normally disabling the CRTC would be enough to also invoke our >> pm_runtime callback to do the final clock disable etc., however when a >> system suspend is in-progress, the core forcibly takes a runtime >> reference on all devices - preventing any pm_runtime paths from >> running. > >I thought this was fixed. At least I remember we had to add some special >calls to i915 to opt out of the "do runtime pm as part of suspend/resume" >behaviour, since it doesn't match what we needed. > >See > >commit aae4518b3124b29f8dc81c829c704fd2df72e98b >Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> >Date: Fri May 16 02:46:50 2014 +0200 > > PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily > >So I thought this stuff was supposed to work now. Adding Rafael Wyzocki, >he's done plenty presentations recently about exactly this. AFAIK direct-complete is a different thing - related, but not involved here. Ayan's patch is to deal with the case where the device is active (runtime state = active), when a system suspend is triggered. The core takes its reference (leaving direct-complete devices 'suspended' if possible, but our device is 'active' and so direct-complete doesn't apply) and then we start the system suspend and disable the CRTC. Normally, after the CRTC is disabled, we rely on PM-core to notice we can be runtime suspended, but it won't do this during system suspend because of the reference PM-core took, and so we need to force the suspend ourselves. > >> This means that after the CRTC is disabled in ->suspend(), our normal >> pm_runtime path will not be invoked, and so the things done in >> malidp_runtime_pm_suspend() will never happen. >> >> We were just following the advice in the kernel-doc to deal with this. >> >> The alternative would be to call malidp_runtime_pm_{suspend,resume} >> from the "not late" hooks, but I'd ask why? >> >> > Also, you still haven't explained what exactly the dependency is. >> >> Because there isn't one :-) > >Hm, if there really isn't one, then I guess it's ok. But it's way too easy >to screw this up, have an accidental depency on a different device. And >then you try to fix this up. Having a suspend_late hook still smells fishy >to me, but I might be out of the loop. >-Daniel > Hopefully Rafael can set us straight. The kerneldoc doesn't make suspend_late sound exceptional, but kernel-doc isn't perfect :-) Thanks for the review, -Brian > > >> >> Thanks, >> -Brian >> >> > -Daniel >> > >> > > >> > > > >> > --- >> > > > >> > drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ >> > > > >> > 1 file changed, 17 insertions(+) >> > > > >> > >> > > > >> > diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c >> > > > >> > index bd44a6d..f6124d8 100644 >> > > > >> > --- a/drivers/gpu/drm/arm/malidp_drv.c >> > > > >> > +++ b/drivers/gpu/drm/arm/malidp_drv.c >> > > > >> > @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) >> > > > >> > return 0; >> > > > >> > } >> > > > >> > >> > > > >> > +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) >> > > > >> > +{ >> > > > >> > + if (!pm_runtime_status_suspended(dev)) { >> > > > >> > + malidp_runtime_pm_suspend(dev); >> > > > >> > + pm_runtime_set_suspended(dev); >> > > > >> > + } >> > > > >> > + return 0; >> > > > >> > +} >> > > > >> > + >> > > > >> > +static int __maybe_unused malidp_pm_resume_early(struct device *dev) >> > > > >> > +{ >> > > > >> > + malidp_runtime_pm_resume(dev); >> > > > >> > + pm_runtime_set_active(dev); >> > > > >> > + return 0; >> > > > >> > +} >> > > > >> > + >> > > > >> > static const struct dev_pm_ops malidp_pm_ops = { >> > > > >> > SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ >> > > > >> > + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ >> > > > >> > SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) >> > > > >> > }; >> > > > >> > >> > > > >> > -- >> > > > >> > 2.7.4 >> > > > >> > >> > > > >> > _______________________________________________ >> > > > >> > dri-devel mailing list >> > > > >> > dri-devel@lists.freedesktop.org >> > > > >> > https://lists.freedesktop.org/mailman/listinfo/dri-devel >> > > > >> >> > > > >> -- >> > > > >> Daniel Vetter >> > > > >> Software Engineer, Intel Corporation >> > > > >> http://blog.ffwll.ch >> > > > >> _______________________________________________ >> > > > >> dri-devel mailing list >> > > > >> dri-devel@lists.freedesktop.org >> > > > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel >> > > > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. >> > > > > _______________________________________________ >> > > > > dri-devel mailing list >> > > > > dri-devel@lists.freedesktop.org >> > > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel >> > > > >> > > > >> > > > >> > > > -- >> > > > Daniel Vetter >> > > > Software Engineer, Intel Corporation >> > > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch >> > >> > -- >> > Daniel Vetter >> > Software Engineer, Intel Corporation >> > http://blog.ffwll.ch > >-- >Daniel Vetter >Software Engineer, Intel Corporation >http://blog.ffwll.ch
diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c index bd44a6d..f6124d8 100644 --- a/drivers/gpu/drm/arm/malidp_drv.c +++ b/drivers/gpu/drm/arm/malidp_drv.c @@ -766,8 +766,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev) return 0; } +static int __maybe_unused malidp_pm_suspend_late(struct device *dev) +{ + if (!pm_runtime_status_suspended(dev)) { + malidp_runtime_pm_suspend(dev); + pm_runtime_set_suspended(dev); + } + return 0; +} + +static int __maybe_unused malidp_pm_resume_early(struct device *dev) +{ + malidp_runtime_pm_resume(dev); + pm_runtime_set_active(dev); + return 0; +} + static const struct dev_pm_ops malidp_pm_ops = { SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \ + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \ SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL) };
malidp_pm_suspend_late checks if the runtime status is not suspended and if so, invokes malidp_runtime_pm_suspend which disables the display engine/core interrupts and the clocks. It sets the runtime status as suspended. Subsequently, malidp_pm_resume_early will invoke malidp_runtime_pm_resume which enables the clocks and the interrupts (previously disabled) and sets the runtime status as active. Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com> Change-Id: I5f8c3d28f076314a1c9da2a46760a9c37039ccda --- drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)