[meta-freescale] Question on CPU frequency scaling on linux-fslc

[Andreas Müller]

Hi Fabio,
> >
> > Have a Variscite VarSOM running linux-fslc with devicetree
> > imx6q-var-som-vsc.dts from meta-freescale-3rdparty. The frequencies
> > available on machine are: 396/792/996MHz.
> >
> > Looking into linux-fslc arch/arm/boot/dts/imx6q.dtsi (this is what
> > imx6q-var-som-vsc.dts includes) I would expect 396/792/852/996/1200
> > MHz.
> >
> > Any ideas where I lost frequencies (think I had similar somewhere but
> > cannot remember - sigh)?
>
> The imx6 cpufreq driver reads the "speed grading" fuses in order to
> determine what are the operating frequencies that will be populated,
> so what you see is the normal behavior.
>
> On a different topic: I remember you have been trying Etnaviv with
> linux-fslc. One suggestion I could give you regarding performance is
> to drop the CONFIG_PROVE_LOCKING=y option from imx_v6_v7_deffconfig.
>
> Hope this helps.

Yes definitely: It does not happen too often that I ask one question
and get two helpful answers.

* Frequency scaling: Now I know there is no issue - cross checked with
old linux-imx - behaves identical.
* CONFIG_PROVE_LOCKING: Did let the horses turn: glmark2 changes from
81 to 84 fps. This is a performance enhancement but I am not sure if
it is worth to give up CONFIG_PROVE_LOCKING for it.

While we are at entnaviv performance: Strange is that our Qml based
application seems to perform better on etnaviv. This is not exactly
what glmark suggests: For vivante blob I remember glmark values
250-260 / etnaviv results are 80+. Wonder if the closed source driver
was optimized for glmark :)

Thanks

Andreas