Re: [PATCH 3/3] PCI/DPC: Await readiness of secondary bus after reset

[Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com>]

HI,

On 12/31/22 10:33 AM, Lukas Wunner wrote:
> We're calling pci_bridge_wait_for_secondary_bus() after performing a
> Secondary Bus Reset, but neglect to do the same after coming out of a
> DPC-induced Hot Reset.  As a result, we're not observing the delays
> prescribed by PCIe r6.0 sec 6.6.1 and may access devices on the
> secondary bus before they're ready.  Fix it.

Please remove "we" usage. Otherwise, looks good.

> 
> Tested-by: Ravi Kishore Koppuravuri <ravi.kishore.koppuravuri@intel.com>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> Cc: stable@vger.kernel.org
> ---
>  drivers/pci/pci.c      | 3 ---
>  drivers/pci/pci.h      | 3 +++
>  drivers/pci/pcie/dpc.c | 4 ++--
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index b0b49243a908..19fe0ef0e583 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -167,9 +167,6 @@ static int __init pcie_port_pm_setup(char *str)
>  }
>  __setup("pcie_port_pm=", pcie_port_pm_setup);
>  
> -/* Time to wait after a reset for device to become responsive */
> -#define PCIE_RESET_READY_POLL_MS 60000
> -
>  /**
>   * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
>   * @bus: pointer to PCI bus structure to search
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 40758248dd80..b72fd888379b 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -7,6 +7,9 @@
>  /* Number of possible devfns: 0.0 to 1f.7 inclusive */
>  #define MAX_NR_DEVFNS 256
>  
> +/* Time to wait after a reset for device to become responsive */
> +#define PCIE_RESET_READY_POLL_MS 60000
> +
>  #define PCI_FIND_CAP_TTL	48
>  
>  #define PCI_VSEC_ID_INTEL_TBT	0x1234	/* Thunderbolt */
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index f5ffea17c7f8..a5d7c69b764e 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -170,8 +170,8 @@ pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
>  	pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
>  			      PCI_EXP_DPC_STATUS_TRIGGER);
>  
> -	if (!pcie_wait_for_link(pdev, true)) {
> -		pci_info(pdev, "Data Link Layer Link Active not set in 1000 msec\n");
> +	if (pci_bridge_wait_for_secondary_bus(pdev, "DPC",
> +					      PCIE_RESET_READY_POLL_MS)) {
>  		clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
>  		ret = PCI_ERS_RESULT_DISCONNECT;
>  	} else {

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer