From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: USB Host port inoperative after kexec on Beagleboard Date: Mon, 9 Jan 2012 23:03:31 +0000 Message-ID: <20120109230331.GA23308@mudshark.cambridge.arm.com> References: <20120109225403.GB23090@mudshark.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20120109225403.GB23090-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kexec-bounces-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Errors-To: kexec-bounces+glkk-kexec=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Peter Chubb Cc: "linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-omap@vger.kernel.org On Mon, Jan 09, 2012 at 10:54:03PM +0000, Will Deacon wrote: > On Mon, Jan 09, 2012 at 10:09:54PM +0000, Peter Chubb wrote: > > > > Hi Will, > > Hi Peter [adding linux-arm-kernel], *Actually* adding linux-arm-kernel this time... > > > Thanks for the fixes to kexec for ARM that went into mainline this > > week. Mostly things work now. > > Great, that's good to hear! > > > One issue: the USB EHCI port on the (rev C2) beagleboard doesn't > > work after a kexec. During boot after kexec, the host device is > > detected and initialised, but nothing plugged in works, even when > > everything was working corectly before the kexec. Das U-boot > > must set up something that is then undone during the kexec reboot. > > Ouch. Have you had a chance to look at the u-boot sources to see what it > does? > > > I've traced all calls to clk_enable() and clk_disable(), and > > everything looks all right --- in particular I can't see > > anything explicitly disabled during kexec that isn't reenabled > > during boot of the subsequent kernel. > > > > Voltages that I can measure look correct on the port. > > > > Do you have any suggestions as to what else could be wrong? > > I'm afraid I'm not familiar with the Beagleboard, so I can't begin to guess. > Have you tried re-initialising the host controller in the new kernel > manually (perhaps my building the driver as a module and {un}loading it a > few times?). It could be that some hardware state persists across the kexec > and it just needs resetting. > > Will