On Fri, May 24, 2019 at 06:30:20PM +0200, Hans de Goede wrote:
> The GOP sometimes initializes the pclk at a (slightly) different frequency
> then the pclk which we've calculated.
>
> This commit makes the DSI code read-back the pclk set by the GOP and
> if that is within a reasonable margin of the calculated pclk, uses
> that instead.
>
> This fixes the first modeset being a full modeset instead of a
> fast modeset on systems where the GOP pclk is different.
>
> Changes in v2:
> -Use intel_encoder_current_mode() to get the pclk setup by the GOP
>
> Changes in v3:
> -Back to the readback approach, skipping the dsi_pll.ctrl / .dev checks
> in intel_pipe_config_compare() when adjust is set leads to:
> [drm:pipe_config_err [i915]] *ERROR* mismatch in dsi_pll.ctrl (...)
> [drm:pipe_config_err [i915]] *ERROR* mismatch in dsi_pll.div (...)
> -Do the readback and pclk overriding from vlv_dsi_init(), rather then from
> intel_dsi_vbt_init() as the vbt code should not be touching the hw
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/vlv_dsi.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/vlv_dsi.c b/drivers/gpu/drm/i915/vlv_dsi.c
> index 3329ccf3b346..49975dd84ff4 100644
> --- a/drivers/gpu/drm/i915/vlv_dsi.c
> +++ b/drivers/gpu/drm/i915/vlv_dsi.c
> @@ -1701,7 +1701,7 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
> struct drm_encoder *encoder;
> struct intel_connector *intel_connector;
> struct drm_connector *connector;
> - struct drm_display_mode *fixed_mode;
> + struct drm_display_mode *current_mode, *fixed_mode;
> enum port port;
>
> DRM_DEBUG_KMS("\n");
> @@ -1745,6 +1745,9 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
> intel_connector->get_hw_state = intel_connector_get_hw_state;
>
> intel_encoder->port = port;
> + intel_encoder->type = INTEL_OUTPUT_DSI;
> + intel_encoder->power_domain = POWER_DOMAIN_PORT_DSI;
> + intel_encoder->cloneable = 0;
>
> /*
> * On BYT/CHV, pipe A maps to MIPI DSI port A, pipe B maps to MIPI DSI
> @@ -1782,6 +1785,20 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
> goto err;
> }
>
> + /* Use clock read-back from current hw-state for fastboot */
> + current_mode = intel_encoder_current_mode(intel_encoder);
> + if (current_mode) {
> + DRM_DEBUG_KMS("Calculated pclk %d GOP %d\n",
> + intel_dsi->pclk, current_mode->clock);
> + if (intel_fuzzy_clock_check(intel_dsi->pclk,
> + current_mode->clock)) {
> + DRM_DEBUG_KMS("Using GOP pclk\n");
> + intel_dsi->pclk = current_mode->clock;
> + }
I wonder if we should be checking whether the mode is otherwise
identical to whatever we got from VBT? Though I suppose that shouldn't
really happen.
The whole dsi clock handling is a proper mess, but looks like ->pclk
is supposed to be the burst clock so I think this should end up doing
more or less the right thing because we seem to stuffing the DPLL
readout into the mode->clock.
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> +
> + kfree(current_mode);
> + }
> +
> vlv_dphy_param_init(intel_dsi);
>
> /*
> @@ -1799,9 +1816,6 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
> }
> }
>
> - intel_encoder->type = INTEL_OUTPUT_DSI;
> - intel_encoder->power_domain = POWER_DOMAIN_PORT_DSI;
> - intel_encoder->cloneable = 0;
> drm_connector_init(dev, connector, &intel_dsi_connector_funcs,
> DRM_MODE_CONNECTOR_DSI);
>
> --
> 2.21.0
--
Ville Syrjälä
Intel
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