Re: OMAP DSS2 coming out of OFF mode without restoring context

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

On Fri, 2010-07-30 at 13:09 +0200, ext Menon, Nishanth wrote:
> ----- Original message -----
> > Hi,
> > 
> > On Thu, 2010-07-29 at 23:29 +0200, ext Laine Walker-Avina wrote:
> > > Hi,
> > > 
> > > I'm having a problem where the DSS driver isn't restoring the
> > > framebuffer parameters after going in and out of blanking with OFF
> > > mode enabled. The problem appears to be in dss_get_ctx_id() in that
> > > pdata->get_last_off_on_transaction_id is 0. Commenting out the call to
> > > dss_need_ctx_restore() in dss_clk_enable() appears to do the right
> > > thing. I'm using the current master branch of linux-omap.
> > 
> > You need to fill the func pointer in the board file:
> > 
> > static struct omap_dss_board_info xxx_dss_data = {
> >                 .get_last_off_on_transaction_id > > omap_pm_get_dev_context_loss_count,
> > 
> none of l-o board files seem to do this. I guess
> with off capable master, we need this to be 
> defaulted under CONFIG_PM within dss/core itself?
> I mean the defaults prevent display function
> at off, so why ask all boards to fill it up?

If the PM stuff in linux tree starts to be in working order, then yes,
we need some better solution.

I'm not quite sure what the options are, but I was told that the correct
way to get context loss count is as above, fill the platform_data in the
board file with a pointer to omap_pm_get_dev_context_loss_count().

So if that is still the proper way, then we need a "DSS platform
initialization" function that the board files can call, which then fills
the platform_data with correct data.

But this will still require modifying every board file that uses DSS.
Then again, every board file needs anyway DSS code, so perhaps that's
not such a big issue.

For this particular case there's not much benefit having a separate
initialization function. On the contrary, it'll just have more code
lines. But I think there will be some more platform DSS stuff (like
pinmuxing) which can then use the same mechanism.

 Tomi