[coreboot] disabling bios usb stack

[ron minnich]

This is really interesting information, thanks.

This embedded USB stack problem actually impacts HPC applications.
This type of periodic interference can cause big troubles when you
have lots of nodes.

Look for "the case of the missing supercomputer performance" for a
classic paper. In that case, a 1/30 hz (i.e. lpd dropping out of
select every 30 seconds on 2048 nodes) was worth a couple tens of
millions of dollars of performance.

I'm amazed that the embedded USB stack problems are WORSE, not better,
than they were a few years back. The x86 world just keeps getting more
backwards. I'm sorry to see the ARM V8 world trying to emulate it.

ron

On Tue, Aug 26, 2014 at 3:14 PM, Антон Кочков <anton.kochkov at gmail.com> wrote:
> Hello,
>
> Just checked some binaries - PEI USB driver is loading anyway, no
> checking for any setup option, so I guess it will be very hard even
> with the unpacking UEFI image and removing these drivers. Also in most
> UEFI systems big part of USB driver working in SMM mode, so it will be
> hard to patch this code on the fly.
> Best regards,
> Anton Kochkov.
>
>
> On Wed, Aug 27, 2014 at 1:23 AM, Carl-Daniel Hailfinger
> <c-d.hailfinger.devel.2006 at gmx.net> wrote:
>> Hi Ron,
>>
>> Am 26.08.2014 00:22 schrieb ron minnich:
>>> disabling the usb stack is the goal in this case.
>>
>> AFAIK it's called "USB keyboard support", "USB legacy support" or
>> something similar in most BIOSes. This internally maps a USB keyboard to
>> a virtual PS/2 keyboard and sometimes has quite a few issues. If that's
>> what your friend meant, disabling it should be straightforward in the
>> BIOS menu.
>> However, if your friend is a victim of EFI, I fear he is beyond help
>> except for trying coreboot.
>>
>> Regards,
>> Carl-Daniel
>>
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