DSS2 Query: Use of FIFO preload values

DSS2 Query: Use of FIFO preload values

[Taneja, Archit]

Hi,

I was going through the DSS2 code and was unable to find a place
where we set the 11th bit in DISPC_GFX_ATTRIBUTES or the 19th bit
in DISPC_VIDn_ATTRIBUTES.

Setting these bits ensures that the DISPC FIFO's fill up to the
high threshold value specified by us instead of the preload values.

Is this done on purpose or it got missed out?

Thanks,

Archit

Re: DSS2 Query: Use of FIFO preload values

[Tomi Valkeinen]

On Tue, 2010-11-09 at 05:20 +0100, ext Taneja, Archit wrote:
> Hi,
> 
> I was going through the DSS2 code and was unable to find a place
> where we set the 11th bit in DISPC_GFX_ATTRIBUTES or the 19th bit
> in DISPC_VIDn_ATTRIBUTES.
> 
> Setting these bits ensures that the DISPC FIFO's fill up to the
> high threshold value specified by us instead of the preload values.
> 
> Is this done on purpose or it got missed out?

A bit both. The TRM is quite unclear about fifo threshold and preload
configuration, and I've never understood how to configure them for
different interfaces. The current setup is mostly configured in such a
way that things seem to work =).

And if I recall right, even if the bits say that preload values are
used, changing the threshold values still broke things. So, as I said, I
never quite understood how they work.

 Tomi