Re: [PATCH] ath10k: fix core PCI suspend when WoWLAN is supported but disabled

[Brian Norris <briannorris@chromium.org>]

Ping? Any comments? I know there's more than one way to slice this
problem, but it's most definitely a problem...

Brian

On Tue, Sep 19, 2017 at 04:24:16PM -0700, Brian Norris wrote:
> For devices where the FW supports WoWLAN but user-space has not
> configured it, we don't do any PCI-specific suspend/resume operations,
> because mac80211 doesn't call drv_suspend() when !wowlan. This has
> particularly bad effects for some platforms, because we don't stop the
> power-save timer, and if this timer goes off after the PCI controller
> has suspended the link, Bad Things will happen.
> 
> Commit 32faa3f0ee50 ("ath10k: add the PCI PM core suspend/resume ops")
> got some of this right, in that it understood there was a problem on
> non-WoWLAN firmware. But it forgot the $subject case.
> 
> Fix this by moving all the PCI driver suspend/resume logic exclusively
> into the driver PM hooks. This shouldn't affect WoWLAN support much
> (this just gets executed later on).
> 
> I would just as well kill the entirety of ath10k_hif_suspend(), as it's
> not even implemented on the USB or SDIO drivers. I expect that we don't
> need the callback, except to return "supported" (i.e., 0) or "not
> supported" (i.e., -EOPNOTSUPP).
> 
> Fixes: 32faa3f0ee50 ("ath10k: add the PCI PM core suspend/resume ops")
> Fixes: 77258d409ce4 ("ath10k: enable pci soc powersaving")
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> Cc: Ryan Hsu <ryanhsu@qti.qualcomm.com>
> Cc: Kalle Valo <kvalo@qca.qualcomm.com>
> Cc: Michal Kazior <michal.kazior@tieto.com>
> ---
>  drivers/net/wireless/ath/ath10k/pci.c | 24 ++++++++++++++----------
>  1 file changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
> index bc1633945a56..4655c944e3fd 100644
> --- a/drivers/net/wireless/ath/ath10k/pci.c
> +++ b/drivers/net/wireless/ath/ath10k/pci.c
> @@ -2580,6 +2580,12 @@ void ath10k_pci_hif_power_down(struct ath10k *ar)
>  #ifdef CONFIG_PM
>  
>  static int ath10k_pci_hif_suspend(struct ath10k *ar)
> +{
> +	/* Nothing to do; the important stuff is in the driver suspend. */
> +	return 0;
> +}
> +
> +static int ath10k_pci_suspend(struct ath10k *ar)
>  {
>  	/* The grace timer can still be counting down and ar->ps_awake be true.
>  	 * It is known that the device may be asleep after resuming regardless
> @@ -2592,6 +2598,12 @@ static int ath10k_pci_hif_suspend(struct ath10k *ar)
>  }
>  
>  static int ath10k_pci_hif_resume(struct ath10k *ar)
> +{
> +	/* Nothing to do; the important stuff is in the driver resume. */
> +	return 0;
> +}
> +
> +static int ath10k_pci_resume(struct ath10k *ar)
>  {
>  	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
>  	struct pci_dev *pdev = ar_pci->pdev;
> @@ -3403,11 +3415,7 @@ static int ath10k_pci_pm_suspend(struct device *dev)
>  	struct ath10k *ar = dev_get_drvdata(dev);
>  	int ret;
>  
> -	if (test_bit(ATH10K_FW_FEATURE_WOWLAN_SUPPORT,
> -		     ar->running_fw->fw_file.fw_features))
> -		return 0;
> -
> -	ret = ath10k_hif_suspend(ar);
> +	ret = ath10k_pci_suspend(ar);
>  	if (ret)
>  		ath10k_warn(ar, "failed to suspend hif: %d\n", ret);
>  
> @@ -3419,11 +3427,7 @@ static int ath10k_pci_pm_resume(struct device *dev)
>  	struct ath10k *ar = dev_get_drvdata(dev);
>  	int ret;
>  
> -	if (test_bit(ATH10K_FW_FEATURE_WOWLAN_SUPPORT,
> -		     ar->running_fw->fw_file.fw_features))
> -		return 0;
> -
> -	ret = ath10k_hif_resume(ar);
> +	ret = ath10k_pci_resume(ar);
>  	if (ret)
>  		ath10k_warn(ar, "failed to resume hif: %d\n", ret);
>  
> -- 
> 2.14.1.690.gbb1197296e-goog
>