L1NEON bit

[Rach]

Hello ,

I am using NEON instructions.I am using previous uboot from
http://www.angstrom-distribution.org/demo/beagleboard/ means not
latest one.

Does previous uboot have L1NEON bit enable? what is effect on
performance on NEON instructions execution if this bit is not set?

what are other setting in Aux Control register can effect NEON
insruction execution?

Thanks,
rach

[Ian R]

On Jul 20, 7:37 am, Rach <rachi...@gmail.com> wrote:
> Hello ,
>
> I am using NEON instructions.I am using  previous uboot fromhttp://www.angstrom-distribution.org/demo/beagleboard/means not
> latest one.

We have been aware of the L1NEON requirement since Oct 2008 so it is
highly likely that your u-boot is setting L1NEON correctly.

[Rach]

Hi,

How can I check Auxiliary Control register in User Mode that L1NEON
bit is set or not?
Does it other way to check?

Thanks,
rach

[Måns Rullgård]

Rach <rach...@gmail.com> writes:

You can't.

> Does it other way to check?

Hack the kernel to provide the value somewhere.

--
Måns Rullgård
ma...@mansr.com

[Vladimir Pantelic]

+ unsigned long aux;
+ __asm__ __volatile__("mrc p15, 0, %0, c1, c0, 1":"=r" (aux));
+ printk("aux control: %08X\n", aux );

[Rach]

Hi Vladimir,
Thanks to help me.
On Jul 22, 4:17 pm, Vladimir Pantelic <p...@nt.tu-darmstadt.de> wrote:
> Måns Rullgård wrote:
> > Rach<rachi...@gmail.com>  writes:

Where to write this instructions to get aux data in kernel?
As I am using angstrom kernel image so how to write into that one?

Thanks,
rach

[Ian R]

Rach, what is the date on your u-boot (hint: you see the date as it
boots)?
It is really easiest to just update u-boot rather than patching the
kernel to try to read the auxv. No-one else has L1NEON issues any
more...

[Rach]

Hi Ian,

On Jul 23, 4:28 am, Ian R <ian.ricka...@btinternet.com> wrote:
> Rach, what is the date on your u-boot (hint: you see the date as it
> boots)?

U-Boot 2009.01-00013-g52eddcd (Feb 03 2009 - 22:22:56)
Does it have L1NEON enable or L2 cache?

> It is really easiest to just update u-boot rather than patching the

> kernel to try to read the auxv.  No-one else hasL1NEONissues any

> more...
>
> On Jul 22, 6:00 am, Rach <rachi...@gmail.com> wrote:
>
> > Hi Vladimir,
> > Thanks to help me.
> > On Jul 22, 4:17 pm, Vladimir Pantelic <p...@nt.tu-darmstadt.de> wrote:
>
> > > Måns Rullgård wrote:
> > > > Rach<rachi...@gmail.com>  writes:
>
> > > >>  Hi,
>
> > > >>  On Jul 22, 8:37 am, Ian R<ian.ricka...@btinternet.com>  wrote:
> > > >>>  On Jul 20, 7:37 am, Rach<rachi...@gmail.com>  wrote:
>
> > > >>>  >  Hello ,
>
> > > >>>  >  I am using NEON instructions.I am using  previous uboot fromhttp://www.angstrom-distribution.org/demo/beagleboard/meansnot
> > > >>>  >  latest one.
>

> > > >>>  We have been aware of theL1NEONrequirement since Oct 2008 so it is

> > > >>>  highly likely that your u-boot is settingL1NEONcorrectly.
> > > >>  How can I check Auxiliary Control register in User Mode thatL1NEON

> > > >>  bitis set or not?

[Koen Kooi]

Op 23 jul 2009, om 08:06 heeft Rach het volgende geschreven:

>
> Hi Ian,
>
> On Jul 23, 4:28 am, Ian R <ian.ricka...@btinternet.com> wrote:
>> Rach, what is the date on your u-boot (hint: you see the date as it
>> boots)?
> U-Boot 2009.01-00013-g52eddcd (Feb 03 2009 - 22:22:56)
> Does it have L1NEON enable or L2 cache?

That looks like the stock uboot, which is known to break usb and dss,
among other things.

regards,

Koen

[Rach]

Hi Koen,

Means, Does this uboot have L1NEON and L2 cache enable?


Thanks,
rach
> regards,
>
> Koen
>
>  PGP.sig
> < 1KViewDownload

[Siarhei Siamashka]

Thanks for the information. It's really interesting to know as I have been
using stock u-boot too.

Btw, http://elinux.org/BeagleBoard#U-Boot currently says
"Mainline U-Boot has good support for BeagleBoard. Get it by: ..."

Should it be updated with some kind of warning about these known issues?
And are these issues reported/documented somewhere?

--
Best regards,
Siarhei Siamashka