Re: [PATCH 2/2] PCI/LINK: bw_notification: Deduplicate reports for multi-function devices

[<Alex_Gagniuc@Dellteam.com>]

On 3/20/19 6:15 AM, Lukas Wunner wrote:
> 
> [EXTERNAL EMAIL]
> 
> If a multi-function device's bandwidth is already limited when it is
> enumerated, a message is logged only for function 0.  By contrast, when
> downtraining occurs after enumeration, a message is logged for all
> functions.  That's because the former uses pcie_report_downtraining(),
> whereas the latter uses __pcie_print_link_status() (which doesn't filter
> functions != 0).  I am seeing this happen on a MacBookPro9,1 with a GPU
> (function 0) and an integrated HDA controller (function 1).
> 
> Avoid this incongruence by calling pcie_report_downtraining() in both
> cases.

Good catch! Thank you for engineering the fixes.

> Signed-off-by: Lukas Wunner <lukas@wunner.de>

Reviewed-by: Alexandru Gagniuc <alex.gagniuc@dellteam.com>

> ---
>   drivers/pci/pci.h                  | 1 +
>   drivers/pci/pcie/bw_notification.c | 2 +-
>   drivers/pci/probe.c                | 2 +-
>   3 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 224d88634115..d994839a3e24 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -273,6 +273,7 @@ enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev);
>   u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed,
>   			   enum pcie_link_width *width);
>   void __pcie_print_link_status(struct pci_dev *dev, bool verbose);
> +void pcie_report_downtraining(struct pci_dev *dev);
>   
>   /* Single Root I/O Virtualization */
>   struct pci_sriov {
> diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c
> index 69e6ba2558bf..c26045f2a890 100644
> --- a/drivers/pci/pcie/bw_notification.c
> +++ b/drivers/pci/pcie/bw_notification.c
> @@ -76,7 +76,7 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context)
>   	 */
>   	down_read(&pci_bus_sem);
>   	list_for_each_entry(dev, &port->subordinate->devices, bus_list)
> -		__pcie_print_link_status(dev, false);
> +		pcie_report_downtraining(dev);
>   	up_read(&pci_bus_sem);
>   
>   	pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status);
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 2ec0df04e0dc..7e12d0163863 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2388,7 +2388,7 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
>   	return dev;
>   }
>   
> -static void pcie_report_downtraining(struct pci_dev *dev)
> +void pcie_report_downtraining(struct pci_dev *dev)
>   {
>   	if (!pci_is_pcie(dev))
>   		return;
>