Re: v3.4-rc4 DSS PM problem (Was: Re: Problems with 3.4-rc5)

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

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On Mon, 2012-05-14 at 08:36 +0100, Joe Woodward wrote:
> Any news on this?
> 
> This thread seems to have gone a little quiet...

Hi,

I've been doing testing to understand the problem, but so far I don't
have any idea why things go wrong. I haven't found out any logic in
which configuration works and which doesn't. Looks to me that for some
reason the PM prevents DSS from getting data fast enough with certain
fifo thresholds.

I have two ways to avoid the problem, but I've been reluctant to make
patches for those because I feel it's just hiding the problem. One way
is to change DISPC SIDLEMODE or MIDLEMODE to disallow idle/standby. The
other is to use certain fifo threshold values, which just seem to work
for unknown reasons.

Considering that we already have a SIDLEMODE hack in DSS for omap3 when
using DSI, I wonder if the omap3 PM + DSS combination is just plain
broken, and we should disallow idle. I'm not quite sure what are the
implications of that.

I'd appreciate comments from the PM people =).

 Tomi


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