Re: [Linux-kernel-mentees] [PATCH v1 01/12] fbdev: gxfb: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

On Wed, Aug 05, 2020 at 03:19:01PM -0500, Bjorn Helgaas wrote:
> 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.
> 
> s/using legacy/using legacy PCI/
> s/.suspen/.suspend/ (in all these patches)
> 
Oh, that's a blunder. Since most of the drivers in my project need similar
changes, I made a template for commit message. And by mistake I would have
edited the template itself.
> I wouldn't necessarily repost the whole series just for that (unless
> the maintainer wants it), but maybe update your branch so if you have
> occasion to repost for other reasons, this will be fixed.
> 
> This particular driver actually doesn't *do* any of the PCI state or
> device PM state management you mention.  And I don't see the "single
> 'struct dev_pm_ops'" you mention below -- I thought that meant you
> would have a single struct shared between drivers (I think you did
> that for IDE?), but that's not what you're doing.  This driver has
> gxfb_pm_ops, the next has lxfb_pm_ops, etc.
> 
Yeah, the sentence sounds misleading. What I meant was that earlier there
were two pointers for PM, .suspend and .resume. Whereas now there is a single
"struct dev_pm_ops" variable inside pci_driver.
> AFAICT the patches are fine, but the commit logs don't seem exactly
> accurate.
> 
I am fixing it.

Thanks
Vaibhav Gupta
> > 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 <vaibhavgupta40@gmail.com>
> > ---
> >  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
> > 
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