[Intel-gfx] [v2 2/5] drm/i915: Limit max VCO supported in CHV to 6.48GHz

[Daniel Vetter]

On Mon, Feb 16, 2015 at 01:21:34PM +0200, Ville Syrjälä wrote:
> On Mon, Feb 16, 2015 at 03:07:59PM +0530, Vijay Purushothaman wrote:
> > As per the recommendation from PHY team, limit the max vco supported in CHV to 6.48 GHz
> > 
> > Signed-off-by: Vijay Purushothaman <vijay.a.purushothaman at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_display.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 3b0fe9f..4e710f6 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -390,7 +390,7 @@ static const intel_limit_t intel_limits_chv = {
> >  	 * them would make no difference.
> >  	 */
> >  	.dot = { .min = 25000 * 5, .max = 540000 * 5},
> > -	.vco = { .min = 4860000, .max = 6700000 },
> > +	.vco = { .min = 4860000, .max = 6480000 },
> 
> I have a patch here to reduce the minimum to 4.80 GHz, otherwise I can't
> get my 2560x1440 HDMI display working (241.5 MHz clock). With that change
> we still have a gap (233-240 MHz) in the frequencies we can produce.
> Reducing the max to 6.48 GHz will increase that gap to 216-240 MHz, which
> is a bit unfortunate. But if that's the recommendation we should follow
> it I suppose, and hope no HDMI displays will want such frequencies.
> 
> Is there an updated spreadsheet available with the new limits? Quite a
> few of the frequencies in the original spreadsheet did have vco>6.48
> GHz.

Has the updated doc been dug up meanwhile? A big part of review is getting
access to docs and making sure they're up-to-date too ...
-Daniel

> 
> I any case this seems OK, so
> Acked-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> >  	.n = { .min = 1, .max = 1 },
> >  	.m1 = { .min = 2, .max = 2 },
> >  	.m2 = { .min = 24 << 22, .max = 175 << 22 },
> > -- 
> > 1.7.9.5
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch