[PATCH 02/11] PCI: pciehp: Enable Command Completed Interrupt only if supported

[Lorenzo Pieralisi]

On Thu, Aug 18, 2022 at 03:51:31PM +0200, Marek Behún wrote:
> From: Pali Rohár <pali at kernel.org>
> 
> The No Command Completed Support bit in the Slot Capabilities register
> indicates whether Command Completed Interrupt Enable is unsupported.
> 
> We already check whether No Command Completed Support bit is set in
> pcie_wait_cmd(), and do not wait in this case.
> 
> Let's not enable this Command Completed Interrupt at all if NCCS is set,
> so that when users dump configuration space from userspace, the dump
> does not confuse them by saying that Command Completed Interrupt is not
> supported, but it is enabled.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
> Signed-off-by: Marek Behún <kabel at kernel.org>
> ---
> Changes since batch 5:
> - changed commit message, previously we wrote that the change is needed
>   to fix a bug where kernel was waiting for an event which did not
>   come. This turns out to be false. See
>   https://lore.kernel.org/linux-pci/20220818142243.4c046c59@dellmb/T/#u
> ---
>  drivers/pci/hotplug/pciehp_hpc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Hi Bjorn,

this patch is mixed with aardvark specific changes,
please let me know if it is fine for you to merge it.

Thanks,
Lorenzo

> diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
> index 373bb396fe22..838eb6cc3ec7 100644
> --- a/drivers/pci/hotplug/pciehp_hpc.c
> +++ b/drivers/pci/hotplug/pciehp_hpc.c
> @@ -817,7 +817,9 @@ static void pcie_enable_notification(struct controller *ctrl)
>  	else
>  		cmd |= PCI_EXP_SLTCTL_PDCE;
>  	if (!pciehp_poll_mode)
> -		cmd |= PCI_EXP_SLTCTL_HPIE | PCI_EXP_SLTCTL_CCIE;
> +		cmd |= PCI_EXP_SLTCTL_HPIE;
> +	if (!pciehp_poll_mode && !NO_CMD_CMPL(ctrl))
> +		cmd |= PCI_EXP_SLTCTL_CCIE;
>  
>  	mask = (PCI_EXP_SLTCTL_PDCE | PCI_EXP_SLTCTL_ABPE |
>  		PCI_EXP_SLTCTL_PFDE |
> -- 
> 2.35.1
>