Re: [PATCH] usb: host: xhci-plat: fix suspend/resume on xhci-rcar

[Felipe Balbi <balbi@ti.com>]

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On Thu, Oct 09, 2014 at 01:45:47PM +0900, Yoshihiro Shimoda wrote:
> This patch fixes an issue that suspend/resume cannot work correctly
> on xhci-rcar because the xhci driver output the following log:
> 
>         xhci-hcd ee000000.usb: WARN: xHC CMD_RUN timeout
> 
> So, this patch adds to set the XHCI_SLOW_SUSPEND quirk if xhci-rcar.

do you have erratum number confirming this is needed for your platform ?
We really don't want to enable quirks just because they help, we need to
be sure HW is quirky. For example, we triggered the same thing on DRA7xx
(which uses dwc3) but after digging a little, it seems like we're having
memory access latency issues, not a problem with XHCI.

> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
>  This patch is based on the Greg's usb.git / usb-next branch.
>  (commit id : 4ed9a3d455558406cad83d38764ee659de25851c)
> 
>  drivers/usb/host/xhci-plat.c |    6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index 3d78b0c..a266883 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -27,12 +27,18 @@ static struct hc_driver __read_mostly xhci_plat_hc_driver;
>  
>  static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
>  {
> +	struct device_node *of_node = dev->of_node;

add also a blank line here.

>  	/*
>  	 * As of now platform drivers don't provide MSI support so we ensure
>  	 * here that the generic code does not try to make a pci_dev from our
>  	 * dev struct in order to setup MSI
>  	 */
>  	xhci->quirks |= XHCI_PLAT;
> +
> +	/* QUIRK: R-Car xHCI must be suspended extra slowly */

why ? Who says that ? Where's the errata document ?

> +	if (of_device_is_compatible(of_node, "renesas,xhci-r8a7790") ||
> +	    of_device_is_compatible(of_node, "renesas,xhci-r8a7791"))
> +		xhci->quirks |= XHCI_SLOW_SUSPEND;
>  }
>  
>  /* called during probe() after chip reset completes */
> -- 
> 1.7.9.5
> 
> --
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-- 
balbi

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