[+cc Rajat]
On Mon, Dec 22, 2014 at 12:07:03PM -0700, Keith Busch wrote:
> The PCI-e Base specifically says Hot-Plug Surprise capability is for
> removal only, but pciehp checked this to determine if it should handle a
> slot event on device add. Lots of platform's pcie slots don't advertise
> support for surprise removal, but are perfectly capable of handling
> hot-add, so checking surprise removal is not appropriate.
>
> This patch checks the Hot-Plug Capable bit in the slot capabilities to
> determine if the detected presence on is a reliable event instead of
> Hot-Plug Surprise.
>
> Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
This seems reasonable to me, and I applied it to pci/hotplug for v3.20.
Does this fix a bug you've observed? If so, I'll include details or a
pointer in the changelog.
2b3940b60626 ("PCI: pciehp: Remove a non-existent card, regardless of
"surprise" capability") made it so we handle unexpected loss of presence
detect even if the slot doesn't advertise Hot-Plug Surprise. I suppose we
could make a similar argument that if a card shows up, maybe we should do
something with it regardless of what the slot advertises for Hot-Plug
Capable.
> ---
> drivers/pci/hotplug/pciehp.h | 1 +
> drivers/pci/hotplug/pciehp_ctrl.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
> index b115219..b91eefb 100644
> --- a/drivers/pci/hotplug/pciehp.h
> +++ b/drivers/pci/hotplug/pciehp.h
> @@ -126,6 +126,7 @@ struct controller {
> #define ATTN_LED(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_AIP)
> #define PWR_LED(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_PIP)
> #define HP_SUPR_RM(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_HPS)
> +#define HP_CAP(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_HPC)
> #define EMI(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_EIP)
> #define NO_CMD_CMPL(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_NCCS)
> #define PSN(ctrl) (((ctrl)->slot_cap & PCI_EXP_SLTCAP_PSN) >> 19)
> diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
> index ff32e85..996c313 100644
> --- a/drivers/pci/hotplug/pciehp_ctrl.c
> +++ b/drivers/pci/hotplug/pciehp_ctrl.c
> @@ -532,7 +532,7 @@ static void interrupt_event_handler(struct work_struct *work)
> pciehp_green_led_off(p_slot);
> break;
> case INT_PRESENCE_ON:
> - if (!HP_SUPR_RM(ctrl))
> + if (!HP_CAP(ctrl))
> break;
> ctrl_dbg(ctrl, "Surprise Insertion\n");
> handle_surprise_event(p_slot);
> --
> 1.7.10.4
>
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