Re: [PATCH] drm/i915: Do not match JSL in ehl_combo_pll_div_frac_wa_needed()

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 13 Mar 2024, Jonathon Hall <jonathon.hall@puri.sm> wrote:
> Since commit 0c65dc062611 ("drm/i915/jsl: s/JSL/JASPERLAKE for
> platform/subplatform defines"), boot freezes on a Jasper Lake tablet
> (Librem 11), usually with graphical corruption on the eDP display,
> but sometimes just a black screen.  This commit was included in 6.6 and
> later.
>
> That commit was intended to refactor EHL and JSL macros, but the change
> to ehl_combo_pll_div_frac_wa_needed() started matching JSL incorrectly
> when it was only intended to match EHL.
>
> It replaced:
> 	return ((IS_PLATFORM(i915, INTEL_ELKHARTLAKE) &&
> 		 IS_JSL_EHL_DISPLAY_STEP(i915, STEP_B0, STEP_FOREVER)) ||
> with:
> 	return (((IS_ELKHARTLAKE(i915) || IS_JASPERLAKE(i915)) &&
> 		 IS_DISPLAY_STEP(i915, STEP_B0, STEP_FOREVER)) ||
>
> Remove IS_JASPERLAKE() to fix the regression.
>
> Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>
> Cc: stable@vger.kernel.org

Thanks for the patch!

Fixes: 0c65dc062611 ("drm/i915/jsl: s/JSL/JASPERLAKE for platform/subplatform defines")
Cc: <stable@vger.kernel.org> # v6.6+
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dpll_mgr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> index ef57dad1a9cb..57a97880dcb3 100644
> --- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> +++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> @@ -2509,7 +2509,7 @@ static void icl_wrpll_params_populate(struct skl_wrpll_params *params,
>  static bool
>  ehl_combo_pll_div_frac_wa_needed(struct drm_i915_private *i915)
>  {
> -	return (((IS_ELKHARTLAKE(i915) || IS_JASPERLAKE(i915)) &&
> +	return ((IS_ELKHARTLAKE(i915) &&
>  		 IS_DISPLAY_STEP(i915, STEP_B0, STEP_FOREVER)) ||
>  		 IS_TIGERLAKE(i915) || IS_ALDERLAKE_S(i915) || IS_ALDERLAKE_P(i915)) &&
>  		 i915->display.dpll.ref_clks.nssc == 38400;

-- 
Jani Nikula, Intel