RE: [PATCH] usb: host: xhci-rcar: Avoid long wait in xhci_reset()

[Felipe Balbi <felipe.balbi@linux.intel.com>]

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Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> writes:

> Hi Felipe,
>
>> From: Felipe Balbi
>> Sent: Thursday, April 21, 2016 7:05 PM
>> 
>> Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> writes:
>> 
>> > If kernel configuration is CONFIG_USB_XHCI_PLATFORM=y and
>> > CONFIG_USB_XHCI_RCAR is not set, R-Car Gen2/3 will cause long wait
>> > in xhci_reset() because such SoCs need specific initialization.
>> 
>> where is the delay coming from exactly ?
>
> The delay is coming from the following code:
>
> 	ret = xhci_handshake(&xhci->op_regs->command,
> 			CMD_RESET, 0, 10 * 1000 * 1000);
> 	if (ret)
> 		return ret;

okay, and why does reset fail ?

> And, kernel log is the following:
>
> [    1.565605] xhci-hcd ee000000.usb: xHCI Host Controller
> [    1.570636] xhci-hcd ee000000.usb: new USB bus registered, assigned bus number 5
> [   22.270160] xhci-hcd ee000000.usb: can't setup: -110
> [   22.274931] xhci-hcd ee000000.usb: USB bus 5 deregistered
> [   22.280158] xhci-hcd: probe of ee000000.usb failed with error -110
>
> The timestamp is strange to me. But, logs of R-Car H3 (ES1.0) and
> R-Car H2 were the same.

yeah, seems like your system timer is counting twice for each tick.

> Should I revise the commit log in detail?

Sure, but let's first why this is the case. It's unclear, to me at
least, why reset fails.

-- 
balbi

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