From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: [Help 1/2] MUSB: ZiO! CF card reader will trigger a change from MUSB host mode to MUSB peripheral mode Date: Fri, 11 Apr 2008 09:13:50 -0700 Message-ID: <200804110913.51170.david-b@pacbell.net> References: <386072610804070408q16c5ffa1u6a0c2e35295aa327@mail.gmail.com> <386072610804080006g588c7ad9ya4dd8c9c9c6cf827@mail.gmail.com> <386072610804100424l46273f0en9cc531dd7ec876ee@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from smtp120.sbc.mail.sp1.yahoo.com ([69.147.64.93]:39483 "HELO smtp120.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1759521AbYDKQNx (ORCPT ); Fri, 11 Apr 2008 12:13:53 -0400 In-Reply-To: <386072610804100424l46273f0en9cc531dd7ec876ee@mail.gmail.com> Content-Disposition: inline Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Bryan Wu Cc: Felipe Balbi , tony@atomide.com, linux-omap@vger.kernel.org On Thursday 10 April 2008, Bryan Wu wrote: > > =A0And for our development board EZKIT548, it can provide 500mA cur= rent > > =A0at 5V as it claimed in manual > > =A0with a external regular. So from my point of view, this bug is n= ot > > =A0related with 100mA current limit issue. It's *supposed* to be able to provide that much ... steady state. But the issue here is current spikes that cause the voltage to drop too low. Did you stick a scope on that signal and *verify* that the voltage never dropped below the valid level? > These days I tried hard to workaround this issue, but failed: >=20 > - When VBUS_ERR happens in OTG_A_HOST state and the OTG is in > peripheral mode, I try to start a new session and power on VBUS. > - CONNECT IRQ fired and OTG is switch back to host mode. It needs to re-enumerate at this point, including USB reset. > - In CONNECT IRQ handler, I rescan the musb->endpoint[i].in_qh or > musb->endpoint[i].out_qh. Then resume the urb transfer which was > stopped by the wrong VBUS_ERR mode switch IRQ. or just dequeue the ur= b > to call off the transfer. > - But the ZiO does not reply anymore. No IRQ from USB hardware. World > keeps silence. That's compatible with the voltage actually dropping too low, so that the peripheral AND host see the session as broken. Sometimes it can help to put a powered hub in between the musb host and the peripheral ... - Dave -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html