Hi Alen, -----Original Message----- From: Alan Stern [mailto:stern@xxxxxxxxxxxxxxxxxxx] Sent: Monday, July 02, 2012 12:45 PM To: Sadasivan Shaiju Cc: Peter Chen; shaiju shaiju; linux-usb@xxxxxxxxxxxxxxx Subject: RE: usb hub is n't recognised during boot up(sometimes) On Mon, 2 Jul 2012, Sadasivan Shaiju wrote: > On Mon, Jul 2, 2012 at 9:08 AM, shaiju shaiju <shshaiju@xxxxxxxxx> wrote: > > Hi Peter, > > > > I have attached the dmesg for a working case and a non working > > case with CONFIG_USB_DEBUG option set . > > > > Looks like here is what is happening in the case of error . It > > try to use OHCI/UHCI driver instead of EHCI driver and try to > > set the port to fullspeed, instead of high speed . Right. As Peter said, this is caused by a hardware problem. > This happens only some times . Say after 30 reboots the problem > occurs . If it is a hardware problem how it is working in other > cases . Because it is intermittent. Actually that doesn't explain anything; it just means that sometimes the problem occurs and sometimes it goes away. But hardware problems can be like that, whereas software problems tend not to be. In this case, the problem seems to be that some part of the hardware is marginally out of spec. Most of the time it works but sometimes it doesn't. > We have a rate matching hub embedded in the PCH . The hardware used > is Ibex Peak/Jasper Forest . > This is an eUSB . I am not sure how I can try the above . It may be that the electrical connections between the EHCI controller and the rate-matching hub are marginally bad. But the the host controller detects it is a high speed device . But the EHCI try to Run in companion mode forcing it to full speed . Below I am copying the problem area . usb 2-1: new high speed USB device using ehci_hcd and address 2 usb 1-1: link qh256-0001/ffff8801581b2b80 start 1 [1/0 us] ehci_hcd 0000:00:1d.0: port 1 full speed --> companion ---------------------> Here is the problem . ehci_hcd 0000:00:1d.0: GetStatus port 1 status 003801 POWER OWNER sig=j CONNECT hub 2-0:1.0: port 1 not reset yet, waiting 50ms Regards, Shaiju. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
