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Subject: [PATCH v1 06/12] fbdev: nvidia: use generic power management

Drivers using legacy power management .suspen()/.resume() callbacks
have to manage PCI states and device's PM states themselves. They also
need to take care of standard configuration registers.

Switch to generic power management framework using a single
"struct dev_pm_ops" variable to take the unnecessary load from the driver.
This also avoids the need for the driver to directly call most of the PCI
helper functions and device power state control functions, as through
the generic framework PCI Core takes care of the necessary operations,
and drivers are required to do only device-specific jobs.

Signed-off-by: Vaibhav Gupta <[email protected]>
---
drivers/video/fbdev/nvidia/nvidia.c | 64 ++++++++++++++++-------------
1 file changed, 35 insertions(+), 29 deletions(-)

diff --git a/drivers/video/fbdev/nvidia/nvidia.c b/drivers/video/fbdev/nvidia/nvidia.c
index c24de9107958..3a1a4330e0d3 100644
--- a/drivers/video/fbdev/nvidia/nvidia.c
+++ b/drivers/video/fbdev/nvidia/nvidia.c
@@ -1041,10 +1041,9 @@ static struct fb_ops nvidia_fb_ops = {
.fb_sync = nvidiafb_sync,
};

-#ifdef CONFIG_PM
-static int nvidiafb_suspend(struct pci_dev *dev, pm_message_t mesg)
+static int nvidiafb_suspend_late(struct device *dev, pm_message_t mesg)
{
- struct fb_info *info = pci_get_drvdata(dev);
+ struct fb_info *info = dev_get_drvdata(dev);
struct nvidia_par *par = info->par;

if (mesg.event == PM_EVENT_PRETHAW)
@@ -1056,46 +1055,54 @@ static int nvidiafb_suspend(struct pci_dev *dev, pm_message_t mesg)
fb_set_suspend(info, 1);
nvidiafb_blank(FB_BLANK_POWERDOWN, info);
nvidia_write_regs(par, &par->SavedReg);
- pci_save_state(dev);
- pci_disable_device(dev);
- pci_set_power_state(dev, pci_choose_state(dev, mesg));
}
- dev->dev.power.power_state = mesg;
+ dev->power.power_state = mesg;

console_unlock();
return 0;
}

-static int nvidiafb_resume(struct pci_dev *dev)
+static int __maybe_unused nvidiafb_suspend(struct device *dev)
{
- struct fb_info *info = pci_get_drvdata(dev);
- struct nvidia_par *par = info->par;
+ return nvidiafb_suspend_late(dev, PMSG_SUSPEND);
+}

- console_lock();
- pci_set_power_state(dev, PCI_D0);
+static int __maybe_unused nvidiafb_hibernate(struct device *dev)
+{
+ return nvidiafb_suspend_late(dev, PMSG_HIBERNATE);
+}

- if (par->pm_state != PM_EVENT_FREEZE) {
- pci_restore_state(dev);
+static int __maybe_unused nvidiafb_freeze(struct device *dev)
+{
+ return nvidiafb_suspend_late(dev, PMSG_FREEZE);
+}

- if (pci_enable_device(dev))
- goto fail;
+static int __maybe_unused nvidiafb_resume(struct device *dev)
+{
+ struct fb_info *info = dev_get_drvdata(dev);
+ struct nvidia_par *par = info->par;

- pci_set_master(dev);
- }
+ console_lock();

par->pm_state = PM_EVENT_ON;
nvidiafb_set_par(info);
fb_set_suspend (info, 0);
nvidiafb_blank(FB_BLANK_UNBLANK, info);

-fail:
console_unlock();
return 0;
}
-#else
-#define nvidiafb_suspend NULL
-#define nvidiafb_resume NULL
-#endif
+
+static const struct dev_pm_ops nvidiafb_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+ .suspend = nvidiafb_suspend,
+ .resume = nvidiafb_resume,
+ .freeze = nvidiafb_freeze,
+ .thaw = nvidiafb_resume,
+ .poweroff = nvidiafb_hibernate,
+ .restore = nvidiafb_resume,
+#endif /* CONFIG_PM_SLEEP */
+};

static int nvidia_set_fbinfo(struct fb_info *info)
{
@@ -1496,12 +1503,11 @@ static int nvidiafb_setup(char *options)
#endif /* !MODULE */

static struct pci_driver nvidiafb_driver = {
- .name = "nvidiafb",
- .id_table = nvidiafb_pci_tbl,
- .probe = nvidiafb_probe,
- .suspend = nvidiafb_suspend,
- .resume = nvidiafb_resume,
- .remove = nvidiafb_remove,
+ .name = "nvidiafb",
+ .id_table = nvidiafb_pci_tbl,
+ .probe = nvidiafb_probe,
+ .driver.pm = &nvidiafb_pm_ops,
+ .remove = nvidiafb_remove,
};

/* ------------------------------------------------------------------------- *
--
2.27.0

2020-08-05 18:25:36

by Vaibhav Gupta

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On Mon, Aug 10, 2020 at 06:54:58PM +0200, Sam Ravnborg wrote:
> Hi Vaibhav
> On Mon, Aug 10, 2020 at 03:09:48PM +0530, Vaibhav Gupta wrote:
> > On Sat, Aug 08, 2020 at 01:17:46PM +0200, Sam Ravnborg wrote:
> > > Hi Vaibhav
> > >
> > > On Wed, Aug 05, 2020 at 11:37:11PM +0530, Vaibhav Gupta wrote:
> > > > Drivers using legacy power management .suspen()/.resume() callbacks
> > > > have to manage PCI states and device's PM states themselves. They also
> > > > need to take care of standard configuration registers.
> > > >
> > > > Switch to generic power management framework using a single
> > > > "struct dev_pm_ops" variable
> > >
> > > "to take the unnecessary load from the driver."
> > > - I do not parse the above - I cannot see what load is removed.
> > > But the code is simpler which is fine. The drawback is that we now
> > > always link in the suspend_gx functions but hopefultl the linker drops
> > > them later.
> > >
> > > > This also avoids the need for the driver to directly call most of the PCI
> > > > helper functions and device power state control functions, as through
> > > > the generic framework PCI Core takes care of the necessary operations,
> > > > and drivers are required to do only device-specific jobs.
> > > Again, I do not see what calles are removed.
> > > A single check for the state is dropped - anything else?
> > >
> > Yeah, the commit messages are bit misleading, I have modified them.
> > > >
> > > > Signed-off-by: Vaibhav Gupta <[email protected]>
> > > > ---
> > > > drivers/video/fbdev/geode/gxfb.h | 5 ----
> > > > drivers/video/fbdev/geode/gxfb_core.c | 36 ++++++++++++++------------
> > > > drivers/video/fbdev/geode/suspend_gx.c | 4 ---
> > > > 3 files changed, 20 insertions(+), 25 deletions(-)
> > > >
> > > > diff --git a/drivers/video/fbdev/geode/gxfb.h b/drivers/video/fbdev/geode/gxfb.h
> > > > index d2e9c5c8e294..792c111c21e4 100644
> > > > --- a/drivers/video/fbdev/geode/gxfb.h
> > > > +++ b/drivers/video/fbdev/geode/gxfb.h
> > > > @@ -21,7 +21,6 @@ struct gxfb_par {
> > > > void __iomem *dc_regs;
> > > > void __iomem *vid_regs;
> > > > void __iomem *gp_regs;
> > > > -#ifdef CONFIG_PM
> > > > int powered_down;
> > > >
> > > > /* register state, for power management functionality */
> > > > @@ -36,7 +35,6 @@ struct gxfb_par {
> > > > uint64_t fp[FP_REG_COUNT];
> > > >
> > > > uint32_t pal[DC_PAL_COUNT];
> > > > -#endif
> > > > };
> > > >
> > > > unsigned int gx_frame_buffer_size(void);
> > > > @@ -49,11 +47,8 @@ void gx_set_dclk_frequency(struct fb_info *info);
> > > > void gx_configure_display(struct fb_info *info);
> > > > int gx_blank_display(struct fb_info *info, int blank_mode);
> > > >
> > > > -#ifdef CONFIG_PM
> > > > int gx_powerdown(struct fb_info *info);
> > > > int gx_powerup(struct fb_info *info);
> > > > -#endif
> > > > -
> > > >
> > > > /* Graphics Processor registers (table 6-23 from the data book) */
> > > > enum gp_registers {
> > > > diff --git a/drivers/video/fbdev/geode/gxfb_core.c b/drivers/video/fbdev/geode/gxfb_core.c
> > > > index d38a148d4746..44089b331f91 100644
> > > > --- a/drivers/video/fbdev/geode/gxfb_core.c
> > > > +++ b/drivers/video/fbdev/geode/gxfb_core.c
> > > > @@ -322,17 +322,14 @@ static struct fb_info *gxfb_init_fbinfo(struct device *dev)
> > > > return info;
> > > > }
> > > >
> > > > -#ifdef CONFIG_PM
> > > > -static int gxfb_suspend(struct pci_dev *pdev, pm_message_t state)
> > > > +static int __maybe_unused gxfb_suspend(struct device *dev)
> > > > {
> > > > - struct fb_info *info = pci_get_drvdata(pdev);
> > > > + struct fb_info *info = dev_get_drvdata(dev);
> > > I do not see any dev_set_drvdata() so I guess we get a NULL pointer
> > > here which is not intended.
> > > Adding a dev_set_data() to gxfb_probe() would do the trick.
> > >
> > gxfb_probe() invokes pci_set_drvdata(pdev, info) which in turn calls
> > dev_set_drvdata(&pdev->dev, data). Adding dev_get_drvdata() will be redundant.
> OK, not obvious but you are right that calling dev_get_drvdata() would
> be redundant and no need.
> There is a pci_get_drvdata() user left so we cannot just skip it and use
> the dev_set_drvdata() direct.
>
> >
> > > >
> > > > - if (state.event == PM_EVENT_SUSPEND) {
> > > > - console_lock();
> > > > - gx_powerdown(info);
> > > > - fb_set_suspend(info, 1);
> > > > - console_unlock();
> > > > - }
> > > > + console_lock();
> > > > + gx_powerdown(info);
> > > > + fb_set_suspend(info, 1);
> > > > + console_unlock();
> > > >
> > > > /* there's no point in setting PCI states; we emulate PCI, so
> > > > * we don't end up getting power savings anyways */
> > > > @@ -340,9 +337,9 @@ static int gxfb_suspend(struct pci_dev *pdev, pm_message_t state)
> > > > return 0;
> > > > }
> > > >
> > > > -static int gxfb_resume(struct pci_dev *pdev)
> > > > +static int __maybe_unused gxfb_resume(struct device *dev)
> > > > {
> > > > - struct fb_info *info = pci_get_drvdata(pdev);
> > > > + struct fb_info *info = dev_get_drvdata(dev);
> > > > int ret;
> > > >
> > > > console_lock();
> > > > @@ -356,7 +353,6 @@ static int gxfb_resume(struct pci_dev *pdev)
> > > > console_unlock();
> > > > return 0;
> > > > }
> > > > -#endif
> > > >
> > > > static int gxfb_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > > > {
> > > > @@ -467,15 +463,23 @@ static const struct pci_device_id gxfb_id_table[] = {
> > > >
> > > > MODULE_DEVICE_TABLE(pci, gxfb_id_table);
> > > >
> > > > +static const struct dev_pm_ops gxfb_pm_ops = {
> > > > +#ifdef CONFIG_PM_SLEEP
> > > > + .suspend = gxfb_suspend,
> > > > + .resume = gxfb_resume,
> > > > + .freeze = NULL,
> > > > + .thaw = gxfb_resume,
> > > > + .poweroff = NULL,
> > > > + .restore = gxfb_resume,
> > > > +#endif
> > > > +};
> > > Can we use SET_SYSTEM_SLEEP_PM_OPS here?
> > > .freeze will be assigned gxfb_suspend, but gxfb_suspend will anyway be
> > > called as far as I read the code.
> > > Likewise for poweroff.
> > >
> > Earlier, gxfb_suspend() performed each operation just for suspend event.
> > And as it was legacy code, it was invoked by pci_legacy_suspend() for
> > pci_pm_suspend(), pci_pm_freeze() and pci_pm_poweroff().
> > Thus, the code was wrapped inside "if" container:
> > if (state.event == PM_EVENT_SUSPEND) { }
> >
> > After binding it with dev_pm_ops variable, pm->suspend() is invoked by just
> > pci_pm_suspend() which is required.
> >
> > So I removed the "if" container and bind the callback with pm->suspend pointer
> > only.
> Looking at platform.c I got the impression that freeze() would call
> pci_legacy_suspend() anyway - but I may have missind something.
> So I guess this is OK then.
>
> I look forward for next revision with updated changelogs.
Hello Sam,

Yeah, I have updated the logs, will be sending the v2 soon. :)

Thanks
Vaibhav Gupta
>
> Sam
> >
> > Using SET_SYSTEM_PM_OPS will bring back the extra step of invoking gxfb_suspend()
> > for freeze and poweroff, even though the function will do nothing in that case.
> >
> > Vaibhav Gupta
> > > Sam
> > >
> > > > +
> > > > static struct pci_driver gxfb_driver = {
> > > > .name = "gxfb",
> > > > .id_table = gxfb_id_table,
> > > > .probe = gxfb_probe,
> > > > .remove = gxfb_remove,
> > > > -#ifdef CONFIG_PM
> > > > - .suspend = gxfb_suspend,
> > > > - .resume = gxfb_resume,
> > > > -#endif
> > > > + .driver.pm = &gxfb_pm_ops,
> > > > };
> > > >
> > > > #ifndef MODULE
> > > > diff --git a/drivers/video/fbdev/geode/suspend_gx.c b/drivers/video/fbdev/geode/suspend_gx.c
> > > > index 1110a527c35c..8c49d4e98772 100644
> > > > --- a/drivers/video/fbdev/geode/suspend_gx.c
> > > > +++ b/drivers/video/fbdev/geode/suspend_gx.c
> > > > @@ -11,8 +11,6 @@
> > > >
> > > > #include "gxfb.h"
> > > >
> > > > -#ifdef CONFIG_PM
> > > > -
> > > > static void gx_save_regs(struct gxfb_par *par)
> > > > {
> > > > int i;
> > > > @@ -259,5 +257,3 @@ int gx_powerup(struct fb_info *info)
> > > > par->powered_down = 0;
> > > > return 0;
> > > > }
> > > > -
> > > > -#endif
> > > > --
> > > > 2.27.0
> > > >
> > > > _______________________________________________
> > > > dri-devel mailing list
> > > > [email protected]
> > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel

2020-08-10 19:00:44

by Vaibhav Gupta

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2020-08-10 19:02:29

by Vaibhav Gupta

[permalink] [raw]

On Sun, Aug 16, 2020 at 10:16:01PM +0200, Sam Ravnborg wrote:
> Hi Vaibhav
>
> On Tue, Aug 11, 2020 at 12:27:12AM +0530, Vaibhav Gupta wrote:
> > Drivers should do only device-specific jobs. But in general, drivers using
> > legacy PCI PM framework for .suspend()/.resume() have to manage many PCI
> > PM-related tasks themselves which can be done by PCI Core itself. This
> > brings extra load on the driver and it directly calls PCI helper functions
> > to handle them.
> >
> > Although the gxfb driver does not have that extra load,
> Sorry, but I am lost here.
> If this drivers does not have the extra load that you describe here then
> I really cannot see why it is relevant for this driver to describe it.
>
> This is a seldomly touched driver - so it helps if the changelog when we
> finally touch the code is easy to parse.
>
> > we should switch to
> > the new generic framework by updating function signatures and define a
> > "struct dev_pm_ops" variable to bind PM callbacks so that we can remove
> > the legacy .suspend & .resume bindings.
> This part matches the patch - good.
>
> > Additionally, this helps us to
> > remove the unnecessary call to gxfb_suspend() in the event of Freeze and
> > Hibernate, as the function does nothing in their case.
> What I think you are explaining above is that the pci pm support
> will only call the suspend operation in case of suspend, so the
> state.event == PM_EVENT_SUSPEND can be dropped in gxfb_suspend().
>
> For reference later I would prefer that this is explained a bit
> more explicit - not that the changelog needs update anyway.
> >
> > Signed-off-by: Vaibhav Gupta <[email protected]>
> Patch looks good, but please give the changelog one more go.
> I have not checked other patches - but I assume they would benefit
> from a similar clarification.
>
> Sam
>
Hello Sam

I will do the changes as suggested.

Thanks
Vaibhav Gupta
> > ---
> > drivers/video/fbdev/geode/gxfb.h | 5 ----
> > drivers/video/fbdev/geode/gxfb_core.c | 36 ++++++++++++++------------
> > drivers/video/fbdev/geode/suspend_gx.c | 4 ---
> > 3 files changed, 20 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/video/fbdev/geode/gxfb.h b/drivers/video/fbdev/geode/gxfb.h
> > index d2e9c5c8e294..792c111c21e4 100644
> > --- a/drivers/video/fbdev/geode/gxfb.h
> > +++ b/drivers/video/fbdev/geode/gxfb.h
> > @@ -21,7 +21,6 @@ struct gxfb_par {
> > void __iomem *dc_regs;
> > void __iomem *vid_regs;
> > void __iomem *gp_regs;
> > -#ifdef CONFIG_PM
> > int powered_down;
> >
> > /* register state, for power management functionality */
> > @@ -36,7 +35,6 @@ struct gxfb_par {
> > uint64_t fp[FP_REG_COUNT];
> >
> > uint32_t pal[DC_PAL_COUNT];
> > -#endif
> > };
> >
> > unsigned int gx_frame_buffer_size(void);
> > @@ -49,11 +47,8 @@ void gx_set_dclk_frequency(struct fb_info *info);
> > void gx_configure_display(struct fb_info *info);
> > int gx_blank_display(struct fb_info *info, int blank_mode);
> >
> > -#ifdef CONFIG_PM
> > int gx_powerdown(struct fb_info *info);
> > int gx_powerup(struct fb_info *info);
> > -#endif
> > -
> >
> > /* Graphics Processor registers (table 6-23 from the data book) */
> > enum gp_registers {
> > diff --git a/drivers/video/fbdev/geode/gxfb_core.c b/drivers/video/fbdev/geode/gxfb_core.c
> > index d38a148d4746..44089b331f91 100644
> > --- a/drivers/video/fbdev/geode/gxfb_core.c
> > +++ b/drivers/video/fbdev/geode/gxfb_core.c
> > @@ -322,17 +322,14 @@ static struct fb_info *gxfb_init_fbinfo(struct device *dev)
> > return info;
> > }
> >
> > -#ifdef CONFIG_PM
> > -static int gxfb_suspend(struct pci_dev *pdev, pm_message_t state)
> > +static int __maybe_unused gxfb_suspend(struct device *dev)
> > {
> > - struct fb_info *info = pci_get_drvdata(pdev);
> > + struct fb_info *info = dev_get_drvdata(dev);
> >
> > - if (state.event == PM_EVENT_SUSPEND) {
> > - console_lock();
> > - gx_powerdown(info);
> > - fb_set_suspend(info, 1);
> > - console_unlock();
> > - }
> > + console_lock();
> > + gx_powerdown(info);
> > + fb_set_suspend(info, 1);
> > + console_unlock();
> >
> > /* there's no point in setting PCI states; we emulate PCI, so
> > * we don't end up getting power savings anyways */
> > @@ -340,9 +337,9 @@ static int gxfb_suspend(struct pci_dev *pdev, pm_message_t state)
> > return 0;
> > }
> >
> > -static int gxfb_resume(struct pci_dev *pdev)
> > +static int __maybe_unused gxfb_resume(struct device *dev)
> > {
> > - struct fb_info *info = pci_get_drvdata(pdev);
> > + struct fb_info *info = dev_get_drvdata(dev);
> > int ret;
> >
> > console_lock();
> > @@ -356,7 +353,6 @@ static int gxfb_resume(struct pci_dev *pdev)
> > console_unlock();
> > return 0;
> > }
> > -#endif
> >
> > static int gxfb_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > {
> > @@ -467,15 +463,23 @@ static const struct pci_device_id gxfb_id_table[] = {
> >
> > MODULE_DEVICE_TABLE(pci, gxfb_id_table);
> >
> > +static const struct dev_pm_ops gxfb_pm_ops = {
> > +#ifdef CONFIG_PM_SLEEP
> > + .suspend = gxfb_suspend,
> > + .resume = gxfb_resume,
> > + .freeze = NULL,
> > + .thaw = gxfb_resume,
> > + .poweroff = NULL,
> > + .restore = gxfb_resume,
> > +#endif
> > +};
> > +
> > static struct pci_driver gxfb_driver = {
> > .name = "gxfb",
> > .id_table = gxfb_id_table,
> > .probe = gxfb_probe,
> > .remove = gxfb_remove,
> > -#ifdef CONFIG_PM
> > - .suspend = gxfb_suspend,
> > - .resume = gxfb_resume,
> > -#endif
> > + .driver.pm = &gxfb_pm_ops,
> > };
> >
> > #ifndef MODULE
> > diff --git a/drivers/video/fbdev/geode/suspend_gx.c b/drivers/video/fbdev/geode/suspend_gx.c
> > index 1110a527c35c..8c49d4e98772 100644
> > --- a/drivers/video/fbdev/geode/suspend_gx.c
> > +++ b/drivers/video/fbdev/geode/suspend_gx.c
> > @@ -11,8 +11,6 @@
> >
> > #include "gxfb.h"
> >
> > -#ifdef CONFIG_PM
> > -
> > static void gx_save_regs(struct gxfb_par *par)
> > {
> > int i;
> > @@ -259,5 +257,3 @@ int gx_powerup(struct fb_info *info)
> > par->powered_down = 0;
> > return 0;
> > }
> > -
> > -#endif
> > --
> > 2.27.0