Re: 2.6.6-mm2, usb ehci warnings/error?

Re: 2.6.6-mm2, usb ehci warnings/error?

[David Brownell]

> There appear lines like
> 
> usb usb2: string descriptor 0 read error: -108
> 
> bug or feature? They weren't there with 2.6.6-mm1. I have no usb2.0 
> stuff to actually test. My usb1 stuff seems to work though.

Bug; minor, since the only real symptom seems to be messages like
that.  Ignore them for now, I'll make a patch soonish.

It's actually the OHCI driver managing your "usb2" bus,
this is nothing to do with EHCI:

> ohci_hcd 0000:00:02.1: nVidia Corporation nForce2 USB Controller (#2)
> PCI: Setting latency timer of device 0000:00:02.1 to 64
> ohci_hcd 0000:00:02.1: irq 21, pci mem f88fe000
> ohci_hcd 0000:00:02.1: new USB bus registered, assigned bus number 2
> hub 2-0:1.0: USB hub found
> hub 2-0:1.0: 3 ports detected

What's happening?  One of the USB patches makes OHCI suspend
its root hub when it's idle (no devices attached), much like
the UHCI driver has done for some time.  Saves some power.

However, it wrongly marks the controller itself (vs just the
root hub part of it) as having suspended.  That's what causes
the "-108" (-ESHUTDOWN) fault reports, as if the controller were
suspended too.  When the controller is suspended, its registers
are inaccesible so requests to the root hub must fail.

- Dave

Re: 2.6.6-mm2, usb ehci warnings/error?

[Prakash K. Cheemplavam]

David Brownell wrote:
>> There appear lines like
>>
>> usb usb2: string descriptor 0 read error: -108
>>
>> bug or feature? They weren't there with 2.6.6-mm1. I have no usb2.0 
>> stuff to actually test. My usb1 stuff seems to work though.
> 
> 
> Bug; minor, since the only real symptom seems to be messages like
> that.  Ignore them for now, I'll make a patch soonish.


Ok, good. Thanks for the explanation of what is going on, though I don't 
can make too much out of it. ;-)

Prakash

libata and write cache

[Prakash K. Cheemplavam]

Hi,

I am just wondering how to enable write back caching with libata.

dmesg gives me

SCSI device sda: drive cache: write through

I would like to use the drive's wirte caching feature to improve 
performance /I know it is a bit dangerous with a flaky system).

Could anyeone tell me how to do it?

Thanks,

Prakash

Re: 2.6.6-mm2, usb ehci warnings/error?

[David Brownell]

[-- Attachment #1: Type: text/plain, Size: 607 bytes --]

Prakash K. Cheemplavam wrote:
> David Brownell wrote:
> 
>>> There appear lines like
>>>
>>> usb usb2: string descriptor 0 read error: -108
>>>
>>> bug or feature? They weren't there with 2.6.6-mm1. I have no usb2.0 
>>> stuff to actually test. My usb1 stuff seems to work though.
>>
>> Bug; minor, since the only real symptom seems to be messages like
>> that.  Ignore them for now, I'll make a patch soonish.
> 
> Ok, good. Thanks for the explanation of what is going on, though I don't 
> can make too much out of it. ;-)

The short version is:  it's missing this patch.

[ Greg, please merge! ]

- Dave

[-- Attachment #2: patch --]
[-- Type: text/plain, Size: 355 bytes --]

--- bk2/xu26/drivers/usb/host/ohci-hub.c	2004-05-11 18:03:30.000000000 -0700
+++ gadget-2.6/drivers/usb/host/ohci-hub.c	2004-05-13 09:15:18.000000000 -0700
@@ -385,6 +385,7 @@
 			) {
 		ohci_vdbg (ohci, "autosuspend\n");
 		(void) ohci_hub_suspend (&ohci->hcd);
+		ohci->hcd.state = USB_STATE_RUNNING;
 		up (&hcd->self.root_hub->serialize);
 	}
 #endif

Re: 2.6.6-mm2, usb ehci warnings/error?

[Greg KH]

On Fri, May 14, 2004 at 10:04:26AM -0700, David Brownell wrote:
> Prakash K. Cheemplavam wrote:
> >David Brownell wrote:
> >
> >>>There appear lines like
> >>>
> >>>usb usb2: string descriptor 0 read error: -108
> >>>
> >>>bug or feature? They weren't there with 2.6.6-mm1. I have no usb2.0 
> >>>stuff to actually test. My usb1 stuff seems to work though.
> >>
> >>Bug; minor, since the only real symptom seems to be messages like
> >>that.  Ignore them for now, I'll make a patch soonish.
> >
> >Ok, good. Thanks for the explanation of what is going on, though I don't 
> >can make too much out of it. ;-)
> 
> The short version is:  it's missing this patch.
> 
> [ Greg, please merge! ]

Applied, thanks.

greg k-h