On Mon, Jan 22, 2018 at 05:41:31PM +0000, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> Apparently SKL/KBL/CFL need some manual help to get the
> programmed HDMI vswing to stick. Implement the relevant
> workaround (display w/a #1143).
>
> Note that the relevant chicken bits live in a transcoder register
> even though the bits affect a specific DDI port rather than a
> specific transcoder. Hence we must pick the correct transcoder
> register instance based on the port rather than based on the
> cpu_transcoder.
>
> Also note that for completeness I included support for DDI A/E
> in the code even though we never have HDMI on those ports.
>
> v2: CFL needs the w/a as well (Rodrigo and Art)
>
> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Cc: Art Runyan <arthur.j.runyan@xxxxxxxxx>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 8 ++++++--
> drivers/gpu/drm/i915/intel_ddi.c | 42 ++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 48 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 10e1269ad6af..2e6d0dc01dc7 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7012,8 +7012,12 @@ enum {
> #define CHICKEN_TRANS_A 0x420c0
> #define CHICKEN_TRANS_B 0x420c4
> #define CHICKEN_TRANS(trans) _MMIO_TRANS(trans, CHICKEN_TRANS_A, CHICKEN_TRANS_B)
> -#define PSR2_VSC_ENABLE_PROG_HEADER (1<<12)
> -#define PSR2_ADD_VERTICAL_LINE_COUNT (1<<15)
> +#define DDI_TRAINING_OVERRIDE_ENABLE (1<<19)
> +#define DDI_TRAINING_OVERRIDE_VALUE (1<<18)
> +#define DDIE_TRAINING_OVERRIDE_ENABLE (1<<17) /* CHICKEN_TRANS_A only */
> +#define DDIE_TRAINING_OVERRIDE_VALUE (1<<16) /* CHICKEN_TRANS_A only */
> +#define PSR2_ADD_VERTICAL_LINE_COUNT (1<<15)
> +#define PSR2_VSC_ENABLE_PROG_HEADER (1<<12)
>
> #define DISP_ARB_CTL _MMIO(0x45000)
> #define DISP_FBC_MEMORY_WAKE (1<<31)
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 6260a882fbe4..e51559be2e3b 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -2433,6 +2433,48 @@ static void intel_enable_ddi_hdmi(struct intel_encoder *encoder,
> crtc_state->hdmi_high_tmds_clock_ratio,
> crtc_state->hdmi_scrambling);
>
> + /* Display WA #1143: skl,kbl,cfl */
> + if (IS_GEN9_BC(dev_priv)) {
> + /*
> + * For some reason these chicken bits have been
> + * stuffed into a transcoder register, event though
> + * the bits affect a specific DDI port rather than
> + * a specific transcoder.
> + */
> + static const enum transcoder port_to_transcoder[] = {
> + [PORT_A] = TRANSCODER_EDP,
> + [PORT_B] = TRANSCODER_A,
> + [PORT_C] = TRANSCODER_B,
> + [PORT_D] = TRANSCODER_C,
> + [PORT_E] = TRANSCODER_A,
> + };
> + enum transcoder transcoder = port_to_transcoder[port];
> + u32 val;
> +
> + val = I915_READ(CHICKEN_TRANS(transcoder));
> +
> + if (port == PORT_E)
> + val |= DDIE_TRAINING_OVERRIDE_ENABLE |
> + DDIE_TRAINING_OVERRIDE_VALUE;
> + else
> + val |= DDI_TRAINING_OVERRIDE_ENABLE |
> + DDI_TRAINING_OVERRIDE_VALUE;
> +
> + I915_WRITE(CHICKEN_TRANS(transcoder), val);
> + POSTING_READ(CHICKEN_TRANS(transcoder));
> +
> + udelay(1);
> +
> + if (port == PORT_E)
> + val &= ~(DDIE_TRAINING_OVERRIDE_ENABLE |
> + DDIE_TRAINING_OVERRIDE_VALUE);
> + else
> + val &= ~(DDI_TRAINING_OVERRIDE_ENABLE |
> + DDI_TRAINING_OVERRIDE_VALUE);
> +
> + I915_WRITE(CHICKEN_TRANS(transcoder), val);
> + }
> +
> /* In HDMI/DVI mode, the port width, and swing/emphasis values
> * are ignored so nothing special needs to be done besides
> * enabling the port.
> --
> 2.13.6
>
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