[PATCH v3 02/11] drm/tilcdc: implement palette loading for rev1

[Jyri Sarha]

On 11/24/16 11:29, Tomi Valkeinen wrote:
>> @@ -213,6 +274,13 @@ static void tilcdc_crtc_off(struct drm_crtc *crtc, bool shutdown)
>> >  				__func__);
>> >  	}
>> >  
>> > +	/*
>> > +	 * LCDC will not retain the palette when reset. Make sure it gets
>> > +	 * reloaded on tilcdc_crtc_enable().
>> > +	 */
>> > +	if (priv->rev == 1)
>> > +		reinit_completion(&tilcdc_crtc->palette_loaded);
>> > +
> So when the crtc is disabled, you do this, so that on crtc enable the
> driver would load palette? When is the crtc enabled if it hasn't been
> disabled first? In other words, when will the palette loading in
> tilcdc_crtc_enable() _not_ trigger for v1?
> 
> This looks a bit messy to me.
> 
> Why not just load the palette every time on crtc enable? And reinit the
> completion in tilcdc_crtc_load_palette().
> 

My final version loads it at the end of modeset_nofb(), to avoid this:

1. Load the fb address to dma registers with "ingenious" 64 bit write

2. Load the dma registers to a temporary storrage

3. Put palette address in dma registers and load the palette

4. Restore the dma registers (= fb address)

But, sure. I can load the palette every time the mode changes, but not
every time the display is enabled.

Thanks,
Jyri