[PATCH] PCI: mvebu: change delay after reset to the PCIe spec mandated 100ms

Jason Cooper jason at lakedaemon.net
Mon Jan 16 03:44:22 PST 2017


Hi Lucas,

On Mon, Jan 16, 2017 at 12:11:42PM +0100, Lucas Stach wrote:
> The current default of 20ms cause some devices, which are slow to initialize,
> to not show up during the bus scanning. Change this to the PCIe spec mandated
> 100ms and document this in the DT binding.
> 
> From PCIe base spec rev 3.0, chapter "6.6.1. Conventional Reset":
> 
> "To allow components to perform internal initialization, system software must
> wait a specified minimum period following the end of a Conventional Reset of
> one or more devices before it is permitted to issue Configuration Requests to
> those devices.
> 
> With a Downstream Port that does not support Link speeds greater than
> 5.0 GT/s, software must wait a minimum of 100 ms before sending a
> Configuration Request to the device immediately below that Port."
> 
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  Documentation/devicetree/bindings/pci/mvebu-pci.txt | 3 ++-
>  drivers/pci/host/pci-mvebu.c                        | 2 +-
>  2 files changed, 3 insertions(+), 2 deletions(-)

Acked-by: Jason Cooper <jason at lakedaemon.net>

thx,

Jason.



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