linux-kernel - Re: [PATCH v3 2/2] PCI: Reduce FLR delay to 10ms for MSFT devices

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Message-ID: <eb9199fa-1a2a-910c-35f8-ea316a57c55d@linux.intel.com>
Date: Fri, 13 Jun 2025 13:31:27 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: grwhyte@...ux.microsoft.com
cc: linux-pci@...r.kernel.org, shyamsaini@...ux.microsoft.com, 
    code@...icks.com, Okaya@...nel.org, bhelgaas@...gle.com, 
    LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 2/2] PCI: Reduce FLR delay to 10ms for MSFT devices

On Wed, 11 Jun 2025, grwhyte@...ux.microsoft.com wrote:

> From: Graham Whyte <grwhyte@...ux.microsoft.com>
> 
> Add a new quirk to reduce the delay after a FLR to 10ms
> for MSFT devices. These devices complete the FLR well within the default
> 100ms timeframe and this path can be optimized for VF removal during

What is "this path" in this context? Try to avoid vague references like 
that.

> runtime repairs and driver updates. These devices do not support immediate
> readiness or readiness time reporting

When talking about something that relates to PCIe spec, please also refer 
to PCIe spec and use the terminology matching to the spec (+ capitalization).

Missing .

Please also reflow the paragraph as the first line is clearly not full.


This probably belongs more to the previous patch changelog than this one, 
as the justification: I suggest you start by stating the problem. So state 
the spec defined wait (+ spec reference), and why that is problem. Then 
explain the solution in another paragraph.

> Signed-off-by: Graham Whyte <grwhyte@...ux.microsoft.com>
> ---
>  drivers/pci/quirks.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index d7f4ee634263..d704606330bd 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -6335,3 +6335,23 @@ static void pci_mask_replay_timer_timeout(struct pci_dev *pdev)
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_GLI, 0x9750, pci_mask_replay_timer_timeout);
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_GLI, 0x9755, pci_mask_replay_timer_timeout);
>  #endif
> +
> +#define MICROSOFT_2051_SVC 0xb210
> +#define MICROSOFT_2051_MANA_MGMT 0x00b8
> +#define MICROSOFT_2051_MANA_MGMT_GFT 0xb290
> +
> +/*
> + * For devices that don't require the full 100ms sleep
> + * after FLR and do not support immediate readiness or readiness
> + * time reporting
> + */
> +static void pci_fixup_pci_flr_10msec(struct pci_dev *pdev)
> +{
> +	pdev->flr_delay = 10000;

10 * USEC_PER_MSEC

> +}
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MICROSOFT, MICROSOFT_2051_SVC,
> +	pci_fixup_pci_flr_10msec);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MICROSOFT, MICROSOFT_2051_MANA_MGMT,
> +	pci_fixup_pci_flr_10msec);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MICROSOFT, MICROSOFT_2051_MANA_MGMT_GFT,
> +	pci_fixup_pci_flr_10msec);
> 

-- 
 i.