[U-Boot] [linux-sunxi] [u-boot 2/2] sun5i: bump DEBE priority (useful on a10s only)

Siarhei Siamashka
2015-01-19T04:29:47Z

On Sun, 04 Jan 2015 20:49:38 +0100
Hans de Goede <hdegoede@redhat.com> wrote:

> Hi,
>
> On 04-01-15 20:19, Michal Suchanek wrote:
> > Setting magic 'reserved' hpcr bit on sun5i DEBE seems required for
> > smooth HDMI scanout of large frambuffer (eg. 1080p).
> >
> > This fix comes at the cost of some overall memory bandwidth so it
> > might be appropriate to detect a10s and only apply there (and not a13).
>
> Hmm, Sairhei is the expert on this, adding him to the Cc. Sairhei, what
> do you think of the proposed change ?

I don't have A10s hardware, so have no idea and can't test anything
myself.

It would be great to have a better description of what exactly is
happening before the patch. And precisely how the patch is helping.
A description of the test setup and benchmark numbers would be
appreciated. And it would be perfect if somebody else could reproduce
the test and confirm the results.

I may try to check A20 with the bus width artificially reduced
to 16 bits (not a totally unrealistic configuration, since
A20-OLinuXino-LIME board exists). If sun5i and sun7i are similar
enough, then the magic reserved bit may have some effect there too.
But that's a different hardware either way.

--
Best regards,
Siarhei Siamashka