Re: [PATCH net-next 07/14] PCI: Add no PM reset quirk for NVIDIA Spectrum devices

Re: [PATCH net-next 07/14] PCI: Add no PM reset quirk for NVIDIA Spectrum devices

[Simon Horman]

+ linux-pci@vger.kernel.org

On Wed, Nov 15, 2023 at 01:17:16PM +0100, Petr Machata wrote:
> From: Ido Schimmel <idosch@nvidia.com>
> 
> Spectrum-{1,2,3,4} devices report that a D3hot->D0 transition causes a
> reset (i.e., they advertise NoSoftRst-). However, this transition does
> not have any effect on the device: It continues to be operational and
> network ports remain up. Advertising this support makes it seem as if a
> PM reset is viable for these devices. Mark it as unavailable to skip it
> when testing reset methods.
> 
> Before:
> 
>  # cat /sys/bus/pci/devices/0000\:03\:00.0/reset_method
>  pm bus
> 
> After:
> 
>  # cat /sys/bus/pci/devices/0000\:03\:00.0/reset_method
>  bus
> 
> Signed-off-by: Ido Schimmel <idosch@nvidia.com>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Petr Machata <petrm@nvidia.com>

Thanks,

my understanding is that this matches the use-case for which
quirk_no_pm_reset was introduced.

> ---
>  drivers/pci/quirks.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index ea476252280a..d208047d1b8f 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3786,6 +3786,19 @@ static void quirk_no_pm_reset(struct pci_dev *dev)
>  DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_ATI, PCI_ANY_ID,
>  			       PCI_CLASS_DISPLAY_VGA, 8, quirk_no_pm_reset);
>  
> +/*
> + * Spectrum-{1,2,3,4} devices report that a D3hot->D0 transition causes a reset
> + * (i.e., they advertise NoSoftRst-). However, this transition does not have
> + * any effect on the device: It continues to be operational and network ports
> + * remain up. Advertising this support makes it seem as if a PM reset is viable
> + * for these devices. Mark it as unavailable to skip it when testing reset
> + * methods.
> + */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcb84, quirk_no_pm_reset);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf6c, quirk_no_pm_reset);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf70, quirk_no_pm_reset);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf80, quirk_no_pm_reset);
> +
>  /*
>   * Thunderbolt controllers with broken MSI hotplug signaling:
>   * Entire 1st generation (Light Ridge, Eagle Ridge, Light Peak) and part
> -- 
> 2.41.0
> 

Re: [PATCH net-next 08/14] PCI: Add debug print for device ready delay

[Simon Horman]

+ linux-pci@vger.kernel.org

On Wed, Nov 15, 2023 at 01:17:17PM +0100, Petr Machata wrote:
> From: Ido Schimmel <idosch@nvidia.com>
> 
> Currently, the time it took a PCI device to become ready after reset is
> only printed if it was longer than 1000ms ('PCI_RESET_WAIT'). However,
> for debugging purposes it is useful to know this time even if it was
> shorter. For example, with the device I am working on, hardware
> engineers asked to verify that it becomes ready on the first try (no
> delay).
> 
> To that end, add a debug level print that can be enabled using dynamic
> debug. Example:
> 
>  # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
>  # dmesg -c | grep ready
>  # echo "file drivers/pci/pci.c +p" > /sys/kernel/debug/dynamic_debug/control
>  # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
>  # dmesg -c | grep ready
>  [  396.060335] mlxsw_spectrum4 0000:01:00.0: ready 0ms after bus reset
>  # echo "file drivers/pci/pci.c -p" > /sys/kernel/debug/dynamic_debug/control
>  # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
>  # dmesg -c | grep ready
> 
> Signed-off-by: Ido Schimmel <idosch@nvidia.com>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Petr Machata <petrm@nvidia.com>

Reviewed-by: Simon Horman <horms@kernel.org>

> ---
>  drivers/pci/pci.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 55bc3576a985..69d20d585f88 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1219,6 +1219,9 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
>  	if (delay > PCI_RESET_WAIT)
>  		pci_info(dev, "ready %dms after %s\n", delay - 1,
>  			 reset_type);
> +	else
> +		pci_dbg(dev, "ready %dms after %s\n", delay - 1,
> +			reset_type);
>  
>  	return 0;
>  }
> -- 
> 2.41.0
>