Re: [PATCH 1/1] PCI/DPC: Fix TLP Prefix register reading offset

[Bjorn Helgaas]

On Thu, Jan 18, 2024 at 01:08:15PM +0200, Ilpo Järvinen wrote:
> The TLP Prefix Log Register consists of multiple DWORDs (PCIe r6.1 sec
> 7.9.14.13) but the loop in dpc_process_rp_pio_error() keeps reading
> from the first DWORD. Add the iteration count based offset calculation
> into the config read.
> 
> Fixes: f20c4ea49ec4 ("PCI/DPC: Add eDPC support")
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>

Applied to pci/dpc for v6.9 with commit log below, thanks!

    PCI/DPC: Print all TLP Prefixes, not just the first
    
    The TLP Prefix Log Register consists of multiple DWORDs (PCIe r6.1 sec
    7.9.14.13) but the loop in dpc_process_rp_pio_error() keeps reading from
    the first DWORD, so we print only the first PIO TLP Prefix (duplicated
    several times), and we never print the second, third, etc., Prefixes.
    
    Add the iteration count based offset calculation into the config read.
    
    Fixes: f20c4ea49ec4 ("PCI/DPC: Add eDPC support")
    Link: https://lore.kernel.org/r/20240118110815.3867-1-ilpo.jarvinen@xxxxxxxxxxxxxxx
    Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
    [bhelgaas: add user-visible details to commit log]
    Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

> ---
>  drivers/pci/pcie/dpc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index 94111e438241..e5d7c12854fa 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -234,7 +234,7 @@ static void dpc_process_rp_pio_error(struct pci_dev *pdev)
>  
>  	for (i = 0; i < pdev->dpc_rp_log_size - 5; i++) {
>  		pci_read_config_dword(pdev,
> -			cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG, &prefix);
> +			cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG + i * 4, &prefix);
>  		pci_err(pdev, "TLP Prefix Header: dw%d, %#010x\n", i, prefix);
>  	}
>   clear_status:
> -- 
> 2.39.2
>