linux-kernel - Re: [PATCH 5/5] PCI / PM: Decode D3cold power state correctly

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Date:   Mon, 5 Aug 2019 23:14:34 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Linux PCI <linux-pci@...r.kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Keith Busch <keith.busch@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH 5/5] PCI / PM: Decode D3cold power state correctly

On Mon, Aug 5, 2019 at 10:52 PM Bjorn Helgaas <helgaas@...nel.org> wrote:
>
> From: Bjorn Helgaas <bhelgaas@...gle.com>
>
> Use pci_power_name() to print pci_power_t correctly.  This changes:
>
>   "state 0" or "D0"   to   "D0"
>   "state 1" or "D1"   to   "D1"
>   "state 2" or "D2"   to   "D2"
>   "state 3" or "D3"   to   "D3hot"
>   "state 4" or "D4"   to   "D3cold"
>
> Changes dmesg logging only, no other functional change intended.
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

> ---
>  drivers/pci/pci.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index d8686e3cd5eb..17ae2615ac11 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -834,14 +834,16 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
>                 return -EINVAL;
>
>         /*
> -        * Validate current state:
> -        * Can enter D0 from any state, but if we can only go deeper
> -        * to sleep if we're already in a low power state
> +        * Validate transition: We can enter D0 from any state, but if
> +        * we're already in a low-power state, we can only go deeper.  E.g.,
> +        * we can go from D1 to D3, but we can't go directly from D3 to D1;
> +        * we'd have to go from D3 to D0, then to D1.
>          */
>         if (state != PCI_D0 && dev->current_state <= PCI_D3cold
>             && dev->current_state > state) {
> -               pci_err(dev, "invalid power transition (from state %d to %d)\n",
> -                       dev->current_state, state);
> +               pci_err(dev, "invalid power transition (from %s to %s)\n",
> +                       pci_power_name(dev->current_state),
> +                       pci_power_name(state));
>                 return -EINVAL;
>         }
>
> @@ -896,8 +898,8 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
>         pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
>         dev->current_state = pci_power_state(pmcsr);
>         if (dev->current_state != state && printk_ratelimit())
> -               pci_info(dev, "Refused to change power state, currently in D%d\n",
> -                        dev->current_state);
> +               pci_info(dev, "refused to change power state (currently %s)\n",
> +                        pci_power_name(dev->current_state));
>
>         /*
>          * According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
> --
> 2.22.0.770.g0f2c4a37fd-goog
>