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SubjectRe: [PATCH RESEND] PCI: endpoint: Fix clearing start entry in configfs
On Fri, Dec 20, 2019 at 09:24:37PM +0900, Kunihiko Hayashi wrote:
> The value of 'start' entry is no change whenever writing 0 to configfs.
> So the endpoint that stopped once can't restart.
>
> The following command lines are an example restarting endpoint and
> reprogramming configurations after receiving bus-reset.
>
> echo 0 > controllers/66000000.pcie-ep/start
> rm controllers/66000000.pcie-ep/func1
> ln -s functions/pci_epf_test/func1 controllers/66000000.pcie-ep/
> echo 1 > controllers/66000000.pcie-ep/start
>
> However, the first 'echo' can't set 0 to 'start', so the last 'echo' can't
> restart endpoint.

I think your description is not correct - pci_epc_group->start is
just used to check if an endpoint has been started or not (in
pci_epc_epf_unlink() and that's a WARN_ON) but nonetheless this
looks like a bug and ought to be fixed.

I need Kishon's ACK to proceed.

Thanks,
Lorenzo

> Fixes: d74679911610 ("PCI: endpoint: Introduce configfs entry for configuring EP functions")
> Cc: Kishon Vijay Abraham I <kishon@ti.com>
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
> ---
> drivers/pci/endpoint/pci-ep-cfs.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
> index d1288a0..4fead88 100644
> --- a/drivers/pci/endpoint/pci-ep-cfs.c
> +++ b/drivers/pci/endpoint/pci-ep-cfs.c
> @@ -58,6 +58,7 @@ static ssize_t pci_epc_start_store(struct config_item *item, const char *page,
>
> if (!start) {
> pci_epc_stop(epc);
> + epc_group->start = 0;
> return len;
> }
>
> --
> 2.7.4
>

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