[U-Boot] [PATCH] mtest: Disable dcache during test

[Benoît Thébaudeau]

Hi Mike,

On 08/11/2012 05:18 AM, Mike Frysinger wrote:
> On Friday 10 August 2012 15:16:15 Benoît Thébaudeau wrote:
> > mtest is supposed to test many types of memory accesses in many
> > different
> > conditions. If dcache is enabled, memory accesses are likely
> > bursts, and
> > some memory accesses are simply skipped. Hence, dcache should be
> > disabled
> > during mtest operation so that what mtest actually tests is not
> > masked by
> > dcache.
> 
> if you want dcache disabled, then why don't you run `dcache off`
> first ?  i
> think it's useful to be able to do both, and forcing it one way is
> wrong.
> 
> thus, NAK from me.
> -mike

Because you will very likely trust mtest and forget about running `dcache off`
first, so you may then be happy about falsely positive mtest results. Moreover,
I can't find any sense or usefulness in running mtest with dcache enabled.

If there is really a need for running mtest with dcache enabled, an option
(disabled by default) could be added to the command line to tell mtest not to
disable dcache.

Best regards,
Benoît