On Wed, Mar 01, 2023 at 12:10:49PM -0800, Radhakrishna Sripada wrote:
> The commit 2357f2b271ad ("drm/i915/mtl: Initial display workarounds")
> extended the workaround Wa_16015201720 to MTL. However the registers
> that the original WA implemented moved for MTL.
>
> Implement the workaround with the correct register.
>
> v3: Skip clock gating for pipe C, D DMC's and fix the title
>
> Fixes: 2357f2b271ad ("drm/i915/mtl: Initial display workarounds")
> Cc: Matt Atwood <matthew.s.atwood@xxxxxxxxx>
> Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dmc.c | 26 +++++++++++++++++++-----
> drivers/gpu/drm/i915/i915_reg.h | 10 ++++++---
> 2 files changed, 28 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
> index f70ada2357dc..b4283cf319f2 100644
> --- a/drivers/gpu/drm/i915/display/intel_dmc.c
> +++ b/drivers/gpu/drm/i915/display/intel_dmc.c
> @@ -389,15 +389,12 @@ static void disable_all_event_handlers(struct drm_i915_private *i915)
> }
> }
>
> -static void pipedmc_clock_gating_wa(struct drm_i915_private *i915, bool enable)
> +static void adlp_pipedmc_clock_gating_wa(struct drm_i915_private *i915, bool enable)
> {
> enum pipe pipe;
>
> - if (DISPLAY_VER(i915) < 13)
> - return;
> -
> /*
> - * Wa_16015201720:adl-p,dg2, mtl
> + * Wa_16015201720:adl-p,dg2
> * The WA requires clock gating to be disabled all the time
> * for pipe A and B.
> * For pipe C and D clock gating needs to be disabled only
> @@ -413,6 +410,25 @@ static void pipedmc_clock_gating_wa(struct drm_i915_private *i915, bool enable)
> PIPEDMC_GATING_DIS, 0);
> }
>
> +static void mtl_pipedmc_clock_gating_wa(struct drm_i915_private *i915)
> +{
> + /*
> + * Wa_16015201720
> + * The WA requires clock gating to be disabled all the time
> + * for pipe A and B.
> + */
> + intel_de_rmw(i915, GEN9_CLKGATE_DIS_0, 0,
> + MTL_PIPEDMC_GATING_DIS_A | MTL_PIPEDMC_GATING_DIS_B);
> +}
> +
> +static void pipedmc_clock_gating_wa(struct drm_i915_private *i915, bool enable)
> +{
> + if (DISPLAY_VER(i915) >= 14 && enable)
> + return mtl_pipedmc_clock_gating_wa(i915);
> + else if (DISPLAY_VER(i915) == 13)
> + return adlp_pipedmc_clock_gating_wa(i915, enable);
Both of these functions return 'void' so the 'return' on each of these
lines is a bit strange. I'd remove the 'return' at the beginning of
these lines.
> +}
> +
> void intel_dmc_enable_pipe(struct drm_i915_private *i915, enum pipe pipe)
> {
> enum intel_dmc_id dmc_id = PIPE_TO_DMC_ID(pipe);
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c1efa655fb68..7c9ac5b43831 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -1794,9 +1794,13 @@
> * GEN9 clock gating regs
> */
> #define GEN9_CLKGATE_DIS_0 _MMIO(0x46530)
> -#define DARBF_GATING_DIS (1 << 27)
> -#define PWM2_GATING_DIS (1 << 14)
> -#define PWM1_GATING_DIS (1 << 13)
> +#define DARBF_GATING_DIS REG_BIT(27)
> +#define MTL_PIPEDMC_GATING_DIS_A REG_BIT(15)
> +#define MTL_PIPEDMC_GATING_DIS_B REG_BIT(14)
> +#define PWM2_GATING_DIS REG_BIT(14)
> +#define MTL_PIPEDMC_GATING_DIS_C REG_BIT(13)
> +#define PWM1_GATING_DIS REG_BIT(13)
> +#define MTL_PIPEDMC_GATING_DIS_D REG_BIT(12)
It's not really worth adding bits that we don't use anywhere. I'd drop
the DIS_C and DIS_D defines here, otherwise people will wonder whether
it's a mistake that they're added but not used.
Aside from the unnecessary bits here and the returns above, the rest
looks okay, so
Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
with those changes.
Matt
>
> #define GEN9_CLKGATE_DIS_3 _MMIO(0x46538)
> #define TGL_VRH_GATING_DIS REG_BIT(31)
> --
> 2.34.1
>
--
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation
