On Fri, 7 Feb 2025, Keith Busch wrote:
> From: Keith Busch <kbusch@xxxxxxxxxx>
>
> The spec does not provide any upper limit to how long a device may
> return Request Retry Status. It just says "Some devices require a
> lengthy self-initialization sequence to complete". The kernel
> arbitrarily chose 60 seconds since that really ought to be enough. But
> there are devices where this turns out not to be enough.
>
> Since any timeout choice would be arbitrary, and 60 seconds is generally
> more than enough for the majority of hardware, let's make this a
> parameter so an admin can adjust it specifically to their needs if the
> default timeout isn't appropriate.
>
> Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 3 +++
> drivers/pci/pci.c | 6 +++++-
> 2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index fb8752b42ec85..1aed555ef8b40 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4843,6 +4843,9 @@
>
> Note: this may remove isolation between devices
> and may put more devices in an IOMMU group.
> + reset_wait=nn The number of milliseconds to wait after a
> + reset while seeing Request Retry Status.
> + Default is 60000 (1 minute).
> force_floating [S390] Force usage of floating interrupts.
> nomio [S390] Do not use MIO instructions.
> norid [S390] ignore the RID field and force use of
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 869d204a70a37..20817dd5ebba7 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -75,7 +75,8 @@ struct pci_pme_device {
> * limit, but 60 sec ought to be enough for any device to become
> * responsive.
> */
> -#define PCIE_RESET_READY_POLL_MS 60000 /* msec */
> +#define PCIE_RESET_READY_POLL_MS pci_reset_ready_wait
> +unsigned long pci_reset_ready_wait = 60000; /* msec */
I don't think masking variables with defines like that is a good idea.
I also suggest you put the unit as a postfix to the variable name.
> static void pci_dev_d3_sleep(struct pci_dev *dev)
> {
> @@ -6841,6 +6842,9 @@ static int __init pci_setup(char *str)
> disable_acs_redir_param = str + 18;
> } else if (!strncmp(str, "config_acs=", 11)) {
> config_acs_param = str + 11;
> + } else if (!strncmp(str, "reset_wait=", 11)) {
> + pci_reset_ready_wait =
> + simple_strtoul(str + 11, &str, 0);
> } else {
> pr_err("PCI: Unknown option `%s'\n", str);
> }
>
--
i.
