On Monday 10 July 2006 3:21 pm, Vivek Dharmadhikari wrote: > David > > I have configured the mailer to wrap after 76 lines.
You should have tried 76 _columns_ or _characters_ instead; that didn't improve anything. > Hope my response is readable now. Please let me know. > I said I was expecting two queue heads because I could spot one > qh with one qtd linked to it as is given below. Note that the > qhs are dumped after expiry of scsi 30 seconds timer. Right, only one _active_ QH, then there's also the ring head which does not get dumped ... > qh/a1610100 dev2 hs ep1 42002102 40000000 (80008c01 data1 nak4) > a1595120 out len=512 02008c80 urb 81612500 > > But in the above qh, the H bit in dword1 0x42002102 is off. So > I was hoping that there would be one more qh with H bit set to > 1(per ehci spec) and linked to above qh. Is my interpretation > correct ? That was the ring head QH, which gets skipped over by the code used to dump that list. You sent it in an earlier message: > > qh = ehci->async->qh_next.qh; The "ehci->async" QH gets skipped, and it's got the H bit set. > As i see only one qh with H bit off and there are > no active or empty qh attached to it, i think the driver > possibly removed unused/retired qh with H-bit set to 1 > which tends to confuse the host controller. is that possible ? I think you're likely the confused entity, because you weren't dumping the node with the H bit set. > As regards using bus_to_virt(), thanks for pointing out that it > is deprecated. But then how to unmap the bus address to virtual > for qh walkthrough ? You don't do that. You keep a CPU view tree and walk that; the DMA addresses are only used to stuff fields used by the hardware. - Dave > > Thanks. > > Regards > Vivek > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of David > Brownell > Sent: Saturday, July 08, 2006 10:54 AM > To: Vivek Dharmadhikari > Cc: linux-usb-devel@lists.sourceforge.net > Subject: Re: [linux-usb-devel] decoding qh and qtds > > > On Friday 07 July 2006 6:16 pm, Vivek Dharmadhikari wrote: > > Hello David > > > > I posted earlier questions regarding the scanning of qhs and is reproduced > > below > > Is your mailer not capable of wrapping lines correctly? > > > > I used the standard idiom like below to dump all the qh and qtds. > > > > qh = ehci->async->qh_next.qh; > > if(qh) > > { > > do { > > dbg_qh ("ehci-hcd",ehci, qh); > > qh = qh->qh_next.qh; > > } while (qh); > > } > > > > I do the above after the expiry of 30 seconds scsi timer and i always see > > that > > there is only one queue head in the list where as i was expecting at least > > two > > queue head. > > And you expected two of them ... why? From what you had said before, > only one QH would be active, so that's the only one I'd expect to see. > > > > After reading the code, i think only active qh and its associated > > qtds are shown. If a qh has no qtd,then above code fragment won't produce > > all > > the qhs. Is this observation correct ? > > There's always a head, and otherwise the only way an empty qh (no qtds) will > be scheduled is if it's about to be removed. An empty qh is shown, but > it won't have any qtds. > > > > > Alternately, I tried to dump all the qhs by doing something like below > > > > addr = readl(&ehci->regs->async_next); > > addr = le32_to_cpu(addr); /* My system is big endian */ > > qh = (struct ehci_qh *)bus_to_virt(addr); > > Two things wrong there. (a) the low bits of that pointer are > used as hardware type codes, so you need to mask them off; and > (b) bus_to_virt() is deprecated for all kinds of good reasons, > don't use it. > > > > dbg_qh ("ehci-hcd",ehci, (struct ehci_qh *)qh); > > > > addr = le32_to_cpu(qh->hw_next); > > qh = (struct ehci_qh *)bus_to_virt(addr); > > Same things again. > > > > dbg_qh ("ehci-hcd",ehci, (struct ehci_qh *)qh); > > > > The dword1 which contains RL,H,Device Address etc fields obtained using > > above > > code fragment contained wrong values. Obviously i did something wrong > > above. > > What makes you think they are wrong? That should give you a big clue... > > > > What am i missing here ? What is the correct way to dump all qhs either ? > > The correct way is to use the C data structures, and walk them using > normal CPU virtual addresses. If you're paranoid, double check them > as you walk, to make sure the views from the CPU and the controller are > exactly in sync while you walk the data structures. > > - Dave > > > Using Tomcat but need to do more? Need to support web services, security? > Get stuff done quickly with pre-integrated technology to make your job easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 > _______________________________________________ > linux-usb-devel@lists.sourceforge.net > To unsubscribe, use the last form field at: > https://lists.sourceforge.net/lists/listinfo/linux-usb-devel > ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? 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