Re: [RESEND PATCH v1] PCI: replace msleep to save waiting time

[Bjorn Helgaas]

On Mon, Feb 23, 2026 at 02:19:19PM +0800, Hongyu Xie wrote:
> In pcie_wait_for_link_status, using msleep(1) to wait for link status
> change.
> But msleep(1) can sleep for nearly 5ms.
> 
> ftrace shows:
>  0)               |                pcie_wait_for_link_status() {
>  0)   0.500 us    |                  pcie_capability_read_word();
>  0)   0.580 us    |                  pcie_capability_read_word();
>  0) * 10292.26 us |                }
> 
>  after changing to usleep_range.
>  ftrace shows:
> 
>  0)               |                pcie_wait_for_link_status() {
>  0)   0.320 us    |                  pcie_capability_read_word();
>  0)   0.480 us    |                  pcie_capability_read_word();
>  0) # 2483.980 us |                }
> 
>  So fix this by using usleep_range.
> 
> Signed-off-by: Hongyu Xie <xiehongyu1@xxxxxxxxxx>
> ---
>  drivers/pci/pci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index f3244630bfd0..68532e248e51 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4519,7 +4519,7 @@ static int pcie_wait_for_link_status(struct pci_dev *pdev,
>  		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnksta);
>  		if ((lnksta & lnksta_mask) == lnksta_match)
>  			return 0;
> -		msleep(1);
> +		usleep_range(1000, 1100);

Perhaps consider fsleep(), since it's a little more generic and I
don't think there's anything magic about the 100 us range value.

>  	} while (time_before(jiffies, end_jiffies));
>  
>  	return -ETIMEDOUT;
> -- 
> 2.25.1
>