[Intel-gfx] [PATCH 6/9] drm/i915: fix ibx/cpt/ppt dpll limits

[Damien Lespiau]

On Tue, May 21, 2013 at 09:54:56PM +0200, Daniel Vetter wrote:
> Now this was broken in pretty fundamental ways:
> - M1/M2 have been consistently off by 2 and used doc values instead of
>   the two less registers values our code expects.
> - M/N limits often were too small by seemingly arbitrary amounts. I
>   suspect this started to work around issues due to the wrong M1/M2
>   limits.
> 
> Rectify this all and consolidate the limits a bit with a #define where
> the docs say that they should be equal.

So this time I'm reading ibexpeak_xxx.xls

> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 36 +++++++++++-------------------------
>  1 file changed, 11 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 520e340..80698ac 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -217,18 +217,16 @@ static const intel_limit_t intel_limits_pineview_lvds = {
>  		.p2_slow = 14, .p2_fast = 14 },
>  };
>  
> -/* Ironlake / Sandybridge
> - *
> - * We calculate clock using (register_value + 2) for N/M1/M2, so here
> - * the range value for them is (actual_value - 2).
> - */
> +#define ILK_DPLL_M_N_LIMITS \
> +	.n = { .min = 1, .max = 6 }, \
> +	.m = { .min = 79, .max = 127 }, \
> +	.m1 = { .min = 10, .max = 20 }, \
> +	.m2 = { .min = 3, .max = 7 }, \
> +
>  static const intel_limit_t intel_limits_ironlake_dac = {
>  	.dot = { .min = 25000, .max = 350000 },
>  	.vco = { .min = 1760000, .max = 3510000 },
> -	.n = { .min = 1, .max = 5 },
> -	.m = { .min = 79, .max = 127 },
> -	.m1 = { .min = 12, .max = 22 },
> -	.m2 = { .min = 5, .max = 9 },
> +	ILK_DPLL_M_N_LIMITS
>  	.p = { .min = 5, .max = 80 },
>  	.p1 = { .min = 1, .max = 8 },
>  	.p2 = { .dot_limit = 225000,

In ibexpeak_xxxx.xsl I have n between 3 and 7 (so 1,5 seemed correct)
for DAC. It also restrics M between 79 and 118.

> @@ -238,10 +236,7 @@ static const intel_limit_t intel_limits_ironlake_dac = {
>  static const intel_limit_t intel_limits_ironlake_single_lvds = {
>  	.dot = { .min = 25000, .max = 350000 },
>  	.vco = { .min = 1760000, .max = 3510000 },
> -	.n = { .min = 1, .max = 3 },
> -	.m = { .min = 79, .max = 118 },
> -	.m1 = { .min = 12, .max = 22 },
> -	.m2 = { .min = 5, .max = 9 },
> +	ILK_DPLL_M_N_LIMITS
>  	.p = { .min = 28, .max = 112 },
>  	.p1 = { .min = 2, .max = 8 },
>  	.p2 = { .dot_limit = 225000,
> @@ -251,10 +246,7 @@ static const intel_limit_t intel_limits_ironlake_single_lvds = {
>  static const intel_limit_t intel_limits_ironlake_dual_lvds = {
>  	.dot = { .min = 25000, .max = 350000 },
>  	.vco = { .min = 1760000, .max = 3510000 },
> -	.n = { .min = 1, .max = 3 },
> -	.m = { .min = 79, .max = 127 },
> -	.m1 = { .min = 12, .max = 22 },
> -	.m2 = { .min = 5, .max = 9 },
> +	ILK_DPLL_M_N_LIMITS
>  	.p = { .min = 14, .max = 56 },
>  	.p1 = { .min = 2, .max = 8 },
>  	.p2 = { .dot_limit = 225000,

For single channel LVDS with ref clock at 120MHz I have n between 3 and
5 (so 1,3 seemed correct). M is restricted to 79,118 here as well

> @@ -265,10 +257,7 @@ static const intel_limit_t intel_limits_ironlake_dual_lvds = {
>  static const intel_limit_t intel_limits_ironlake_single_lvds_100m = {
>  	.dot = { .min = 25000, .max = 350000 },
>  	.vco = { .min = 1760000, .max = 3510000 },
> -	.n = { .min = 1, .max = 2 },
> -	.m = { .min = 79, .max = 126 },
> -	.m1 = { .min = 12, .max = 22 },
> -	.m2 = { .min = 5, .max = 9 },
> +	ILK_DPLL_M_N_LIMITS
>  	.p = { .min = 28, .max = 112 },
>  	.p1 = { .min = 2, .max = 8 },
>  	.p2 = { .dot_limit = 225000,

For dual channel LVDS, I have n between 3 and 5, so 1,3? M between
79,127

> @@ -278,10 +267,7 @@ static const intel_limit_t intel_limits_ironlake_single_lvds_100m = {
>  static const intel_limit_t intel_limits_ironlake_dual_lvds_100m = {
>  	.dot = { .min = 25000, .max = 350000 },
>  	.vco = { .min = 1760000, .max = 3510000 },
> -	.n = { .min = 1, .max = 3 },
> -	.m = { .min = 79, .max = 126 },
> -	.m1 = { .min = 12, .max = 22 },
> -	.m2 = { .min = 5, .max = 9 },
> +	ILK_DPLL_M_N_LIMITS
>  	.p = { .min = 14, .max = 42 },
>  	.p1 = { .min = 2, .max = 6 },
>  	.p2 = { .dot_limit = 225000,

And there n between 3,4 so (1,2), M was indeed between 79 and 126

-- 
Damien