linux-kernel - Re: Missing USB XHCI and EHCI reset for kexec

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Message-ID: <1397586749.20840.6.camel@vger.seibold.net>
Date:	Tue, 15 Apr 2014 20:32:29 +0200
From:	Stefani Seibold <stefani@...bold.net>
To:	Alan Stern <stern@...land.harvard.edu>
Cc:	linux-usb <linux-usb@...r.kernel.org>,
	linux-kernel@...r.kernel.org, Greg KH <greg@...ah.com>,
	sarah.a.sharp@...ux.intel.com, andreas.brief@...de-schwarz.com
Subject: Re: Missing USB XHCI and EHCI reset for kexec

Am Montag, den 14.04.2014, 13:58 -0400 schrieb Alan Stern:
> On Mon, 14 Apr 2014, Stefani Seibold wrote:
> 
> > > > An other PowerPC device which is nearly eactly the same HW but without  
> > > > this USB HUB works perfectly.
> > > 
> > > Maybe you should replace that hub with a different brand.
> > > 
> > 
> > Thats not possible, because the Hub is soldered on the board. And it is
> > also not a HW issue, since the Hub works perfectly which all previous
> > kernels including 3.4.
> 
> One other thing you can try is to increase the reset timeout in 
> drivers/usb/host/ehci-hub.c.  This is under the USB_PORT_FEAT_RESET 
> case in ehci_hub_control(), around line 1225:
> 
> 				/*
> 				 * caller must wait, then call GetPortStatus
> 				 * usb 2.0 spec says 50 ms resets on root
> 				 */
> 				ehci->reset_done [wIndex] = jiffies
> 						+ msecs_to_jiffies (50);
> 
> Increasing the 50 to 100 or more might help.
> 
> Alan Stern
> 

I tried this, when i increase the value to 1000, the reset and
enumeration process will be faster after a kexec: 28 Seconds vs. 162
Seconds.

- Stefani

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