ACK/Cmnt: [PATCH 1/1] drm/i915/display: Handle lane polarity for DDI port

[Stefan Bader]

On 15.04.21 10:48, Kai-Heng Feng wrote:
> From: Uma Shankar <uma.shankar at intel.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1924238
> 
> Lane Reversal is required for some of the DDI ports. This information
> is populated in VBT and driver should read the same and set the
> polarity while enabling the port. This patch handles the same.
> 
> It helps fix a display blankout issue on DP ports on certain
> platforms.
> 
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Link: https://patchwork.freedesktop.org/patch/msgid/20210211114209.23866-1-uma.shankar@intel.com
cherry picked from commit aaab24bb25e9fc4c8f3a1d9a593d3ace2c4af243)
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---

The patch is now upstream with the same SHA1.

-Stefan

>   drivers/gpu/drm/i915/display/intel_bios.c | 17 +++++++++++++++++
>   drivers/gpu/drm/i915/display/intel_bios.h |  2 ++
>   drivers/gpu/drm/i915/display/intel_ddi.c  |  3 +++
>   3 files changed, 22 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 555e1bd9a34b..c3d345b04b19 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -2701,6 +2701,23 @@ intel_bios_is_lspcon_present(const struct drm_i915_private *i915,
>   	return HAS_LSPCON(i915) && child && child->lspcon;
>   }
>   
> +/**
> + * intel_bios_is_lane_reversal_needed - if lane reversal needed on port
> + * @i915:       i915 device instance
> + * @port:       port to check
> + *
> + * Return true if port requires lane reversal
> + */
> +bool
> +intel_bios_is_lane_reversal_needed(const struct drm_i915_private *i915,
> +				   enum port port)
> +{
> +	const struct child_device_config *child =
> +		i915->vbt.ddi_port_info[port].child;
> +
> +	return child && child->lane_reversal;
> +}
> +
>   enum aux_ch intel_bios_port_aux_ch(struct drm_i915_private *dev_priv,
>   				   enum port port)
>   {
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.h b/drivers/gpu/drm/i915/display/intel_bios.h
> index e29e79faa01b..f25190ecfe97 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.h
> +++ b/drivers/gpu/drm/i915/display/intel_bios.h
> @@ -241,6 +241,8 @@ bool intel_bios_is_port_hpd_inverted(const struct drm_i915_private *i915,
>   				     enum port port);
>   bool intel_bios_is_lspcon_present(const struct drm_i915_private *i915,
>   				  enum port port);
> +bool intel_bios_is_lane_reversal_needed(const struct drm_i915_private *i915,
> +					enum port port);
>   enum aux_ch intel_bios_port_aux_ch(struct drm_i915_private *dev_priv, enum port port);
>   bool intel_bios_get_dsc_params(struct intel_encoder *encoder,
>   			       struct intel_crtc_state *crtc_state,
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 09c0da7c3436..1650bf53da61 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -5665,6 +5665,9 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
>   			intel_de_read(dev_priv, DDI_BUF_CTL(port))
>   			& (DDI_BUF_PORT_REVERSAL | DDI_A_4_LANES);
>   
> +	if (intel_bios_is_lane_reversal_needed(dev_priv, port))
> +		dig_port->saved_port_bits |= DDI_BUF_PORT_REVERSAL;
> +
>   	dig_port->dp.output_reg = INVALID_MMIO_REG;
>   	dig_port->max_lanes = intel_ddi_max_lanes(dig_port);
>   	dig_port->aux_ch = intel_bios_port_aux_ch(dev_priv, port);
> 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <https://lists.ubuntu.com/archives/kernel-team/attachments/20210429/de6a1a37/attachment.sig>