Re: [PATCH] drm/i915: Turn off hsync and vsync on ADPA when disabling crt

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Mar 05, 2013 at 03:33:26PM +0100, Patrik Jakobsson wrote:
> > Accroding to the docs these bits don't exist on PCH platforms.
> > intel_crt_dpms() already has a check for this, so I suppose
> > intel_disable_crt() should have one too.
> >
> > Also I noticed that we seem to have the hsync and vsync disable
> > bits reversed. At least that's what the docs are telling me.
> 
> The PCH check just forces suspend and standby to off and we're only doing dpms
> off in intel_disable_crt() so no need to check it there.

You're right. I assumed that the check would somehow avoid setting
these bits too, but it doesn't. So I guess we don't really care
that they don't exist.

> I'm looking at the 965/G35 PRM and the "sync disable" are defined correctly but
> used incorrectly in intel_disable_crt(). That's what my patch fixes. I haven't
> checked the other PRMs. Is it different on newer hardware?

This is what the docs say:

11:10 Monitor DPMS: (for CRT port) ...
...
00 = ... (will not affect sync pulses)
01 = ... (HSYNC pulses, VSYNC does not)
10 = ... (VSYNC pulses, HSYNC does not)
11 = ... (Neither HSYNC nor VSYNC pulses)

These are our definintions:

#define   ADPA_VSYNC_CNTL_DISABLE (1<<11)
#define   ADPA_HSYNC_CNTL_DISABLE (1<<10)

As you can see they don't match.

-- 
Ville Syrjälä
Intel OTC