On Fri, Jul 03, 2020 at 01:44:26PM +0530, Vaibhav Gupta wrote:
> While upgrading ide_pci_suspend() and ide_pci_resume(), all other source
> files, using same callbacks, were also updated except
> drivers/ide/triflex.c. This is because the driver does not want to power
> off the device during suspend. A quirk was required for the same.
> 
> This patch provides the fix. Another driver,
> drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c, makes use of
> a quirk for similar goal. Hence a similar quirk has been applied for
> triflex.
> 
> Compile-tested only.
> 
> Signed-off-by: Vaibhav Gupta <[email protected]>
> ---
>  drivers/ide/triflex.c | 45 +++++++++++--------------------------------
>  1 file changed, 11 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/ide/triflex.c b/drivers/ide/triflex.c
> index 1886bbfb9e5d..f707f11c296d 100644
> --- a/drivers/ide/triflex.c
> +++ b/drivers/ide/triflex.c
> @@ -100,48 +100,25 @@ static const struct pci_device_id triflex_pci_tbl[] = {
>  };
>  MODULE_DEVICE_TABLE(pci, triflex_pci_tbl);
>  
> -#ifdef CONFIG_PM
> -static int triflex_ide_pci_suspend(struct pci_dev *dev, pm_message_t state)
> -{
> -     /*
> -      * We must not disable or powerdown the device.
> -      * APM bios refuses to suspend if IDE is not accessible.
> -      */
> -     pci_save_state(dev);
> -     return 0;
> -}
> -
> -static int triflex_ide_pci_resume(struct pci_dev *dev)
> +/*
> + * We must not disable or powerdown the device.
> + * APM bios refuses to suspend if IDE is not accessible.
> + */
> +static void triflex_pci_pm_cap_fixup(struct pci_dev *pdev)
>  {
> -     struct ide_host *host = pci_get_drvdata(dev);
> -     int rc;
> -
> -     pci_set_power_state(dev, PCI_D0);
> -
> -     rc = pci_enable_device(dev);
> -     if (rc)
> -             return rc;
> -
> -     pci_restore_state(dev);
> -     pci_set_master(dev);
> -
> -     if (host->init_chipset)
> -             host->init_chipset(dev);
> -
> -     return 0;
> +     dev_info(&pdev->dev, "Disable triflex to be turned off by PCI CORE\n");

I would change this message to "Disabling PCI power management" to be
more like existing messages:

  "PM disabled\n"
  "Disabling PCI power management to avoid bug\n"
  "Disabling PCI power management on camera ISP\n"

> +     pdev->pm_cap = 0;
>  }
> -#else
> -#define triflex_ide_pci_suspend NULL
> -#define triflex_ide_pci_resume NULL
> -#endif
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_COMPAQ,
> +                     PCI_DEVICE_ID_COMPAQ_TRIFLEX_IDE,
> +                     triflex_pci_pm_cap_fixup);

I don't think this needs to be a fixup.  This could be done in the
probe routine (triflex_init_one()).

Doing it as a fixup means the PCI core will check every PCI device
to see if it matches PCI_DEVICE_ID_COMPAQ_TRIFLEX_IDE, which is a
little extra useless overhead and quirks are a little bit magic
because it's not as obvious how they're called.

But since triflex_init_one() is called only for the devices we care
about, you can just do:

  static int triflex_init_one(struct pci_dev *dev, const struct pci_device_id 
*id)
  {
        dev->pm_cap = 0;
        dev_info(...);
        return ide_pci_init_one(dev, &triflex_device, NULL);
  }

>  static struct pci_driver triflex_pci_driver = {
>       .name           = "TRIFLEX_IDE",
>       .id_table       = triflex_pci_tbl,
>       .probe          = triflex_init_one,
>       .remove         = ide_pci_remove,
> -     .suspend        = triflex_ide_pci_suspend,
> -     .resume         = triflex_ide_pci_resume,
> +     .driver.pm      = &ide_pci_pm_ops,
>  };
>  
>  static int __init triflex_ide_init(void)
> -- 
> 2.27.0
> 

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