Re: [solved] Re: USB device not seen by grub

[address@hidden]

On Fri, Dec 4, 2009 at 8:26 PM, Chris Jones <address@hidden> wrote:
> On Thu, Dec 03, 2009 at 05:52:37PM EST, Vladimir 'φ-coder/phcoder' Serbinenko 
> wrote:
>
> [..]
>
>> This is just module loading. I guess your terminal is slow which causes
>> an enormous slowback when loading module. You can using
>
>> debug=usb,uhci,ohci
>> instead of
>> debug=all
>
> I was able to boot the partition I had copied over to the USB stick after
> this:
>
> grub:> debug=uhci,ohci,usbms
> grub:> insmod uhci
> grub:> insmod usbms
> grub:> debug=
>
> Why do I have to enable tracing to make it work?

Yesterday Vladimir wrote:

(quote)
There is an issue that somewhere grub misses a delay between uhci
commands. When enabling debug=all this hang goes away. My laptop has
this issue too. I hope to have time soon to fix it
(/quote)

This makes a lot of sense, the UHCI controller may require some time
for processing certain commands before it can accept the next one, and
tracing slows things down enough to let the controller catch up.  It's
a very good sign (for having a fix soon) that one of the major
programmers has not only reproduced the problem but is affected by it.