Re: [PATCH] PCI: Lengthen reset delay for VideoPropulsion Torrent QN16e card

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Sep 21, 2023 at 04:23:34PM +0200, Lukas Wunner wrote:
> Commit ac91e6980563 ("PCI: Unify delay handling for reset and resume")
> shortened an unconditional 1 sec delay after a Secondary Bus Reset to
> 100 msec for PCIe (per PCIe r6.1 sec 6.6.1).  The 1 sec delay is only
> required for Conventional PCI.
> 
> But it turns out that there are PCIe devices which require a longer
> delay than prescribed before first config space access after reset
> recovery or resume from D3cold:
> 
> Chad reports that a "VideoPropulsion Torrent QN16e" MPEG QAM Modulator
> "raises a PCI system error (PERR), as reported by the IPMI event log,
> and the hardware itself would suffer a catastrophic event, cycling the
> server" unless the longer delay is observed.
> 
> The card is specified to conform to PCIe r1.0 and indeed only supports
> Gen1 speed (2.5 GT/s) according to lspci.  PCIe r1.0 sec 7.6 prescribes
> the same 100 msec delay as PCIe r6.1 sec 6.6.1:
> 
>  "To allow components to perform internal initialization, system software
>   must wait for at least 100 ms from the end of a reset (cold/warm/hot)
>   before it is permitted to issue Configuration Requests"
> 
> The behavior of the Torrent QN16e card thus appears to be a quirk.
> Treat it as such and lengthen the reset delay for this specific device.
> 
> Fixes: ac91e6980563 ("PCI: Unify delay handling for reset and resume")
> Closes: https://lore.kernel.org/linux-pci/DM6PR16MB2844903E34CAB910082DF019B1FAA@DM6PR16MB2844.namprd16.prod.outlook.com/
> Reported-by: Chad Schroeder <CSchroeder@sonifi.com>
> Tested-by: Chad Schroeder <CSchroeder@sonifi.com>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> Cc: stable@vger.kernel.org # v5.4+

Applied to reset for v6.7, thanks.

> ---
>  drivers/pci/quirks.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index eeec1d6f9023..91a15d79c7c4 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -6188,3 +6188,15 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a31, dpc_log_size);
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5020, of_pci_make_dev_node);
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5021, of_pci_make_dev_node);
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_REDHAT, 0x0005, of_pci_make_dev_node);
> +
> +/*
> + * Devices known to require a longer delay before first config space access
> + * after reset recovery or resume from D3cold:
> + *
> + * VideoPropulsion (aka Genroco) Torrent QN16e MPEG QAM Modulator
> + */
> +static void pci_fixup_d3cold_delay_1sec(struct pci_dev *pdev)
> +{
> +	pdev->d3cold_delay = 1000;
> +}
> +DECLARE_PCI_FIXUP_FINAL(0x5555, 0x0004, pci_fixup_d3cold_delay_1sec);
> -- 
> 2.40.1
>