[PATCH 2/4] drm/i915: Respect DP++ adaptor TMDS clock limit
Daniel Vetter
daniel at ffwll.ch
Mon Feb 29 16:02:09 UTC 2016
On Tue, Feb 23, 2016 at 06:46:26PM +0200, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Try to detect the max TMDS clock limit for the DP++ adaptor (if any)
> and take it into account when checking the port clock.
>
> Note that as with the sink (HDMI vs. DVI) TMDS clock limit we'll ignore
> the adaptor TMDS clock limit in the modeset path, in case users are
> already "overclocking" their TMDS links. One subtle change here is that
> we'll have to respect the adaptor TMDS clock limit when we decide whether
> to do 12bpc or 8bpc, otherwise we might end up picking 12bpc and
> accidentally driving the TMDS link out of spec even when the user chose
> a mode that fits wihting the limits at 8bpc. This means you can't
> "overclock" your DP++ dongle at 12bpc anymore, but you can continue to
> do so at 8bpc.
>
> Note that for simplicity we'll use the I2C access method for all dual
> mode adaptors including type 2. Otherwise we'd have to start mixing
> DP AUX and HDMI together. In the future we may need to do that if we
> come across any board designs that don't hook up the DDC pins to the
> DP++ connectors. Such boards would obviously only work with type 2
> dual mode adaptors, and not type 1.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
And on this patch and patch 1:
Cc: drm-intel-fixes at lists.freedesktop.org
I'll review patch 1 too if someone pities me with the spec ;-)
Thanks, Daniel
> ---
> drivers/gpu/drm/i915/intel_drv.h | 3 ++
> drivers/gpu/drm/i915/intel_hdmi.c | 65 ++++++++++++++++++++++++++++++++++-----
> 2 files changed, 60 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 4852049c9ab3..944eacbfb6a9 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -704,6 +704,9 @@ struct cxsr_latency {
> struct intel_hdmi {
> i915_reg_t hdmi_reg;
> int ddc_bus;
> + struct {
> + int max_tmds_clock;
> + } dp_dual_mode;
> bool limited_color_range;
> bool color_range_auto;
> bool has_hdmi_sink;
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 80b44c054087..1e8cfdb18dc7 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -34,6 +34,7 @@
> #include <drm/drm_atomic_helper.h>
> #include <drm/drm_crtc.h>
> #include <drm/drm_edid.h>
> +#include <drm/drm_dp_dual_mode_helper.h>
> #include "intel_drv.h"
> #include <drm/i915_drm.h>
> #include "i915_drv.h"
> @@ -1168,27 +1169,42 @@ static void pch_post_disable_hdmi(struct intel_encoder *encoder)
> intel_disable_hdmi(encoder);
> }
>
> -static int hdmi_port_clock_limit(struct intel_hdmi *hdmi, bool respect_dvi_limit)
> +static int intel_hdmi_source_max_tmds_clock(struct drm_i915_private *dev_priv)
> {
> - struct drm_device *dev = intel_hdmi_to_dev(hdmi);
> -
> - if ((respect_dvi_limit && !hdmi->has_hdmi_sink) || IS_G4X(dev))
> + if (IS_G4X(dev_priv))
> return 165000;
> - else if (IS_HASWELL(dev) || INTEL_INFO(dev)->gen >= 8)
> + else if (IS_HASWELL(dev_priv) || INTEL_INFO(dev_priv)->gen >= 8)
> return 300000;
> else
> return 225000;
> }
>
> +static int hdmi_port_clock_limit(struct intel_hdmi *hdmi,
> + bool respect_downstream_limits)
> +{
> + struct drm_device *dev = intel_hdmi_to_dev(hdmi);
> + int max_tmds_clock = intel_hdmi_source_max_tmds_clock(to_i915(dev));
> +
> + if (respect_downstream_limits) {
> + if (hdmi->dp_dual_mode.max_tmds_clock)
> + max_tmds_clock = min(max_tmds_clock,
> + hdmi->dp_dual_mode.max_tmds_clock);
> + if (!hdmi->has_hdmi_sink)
> + max_tmds_clock = min(max_tmds_clock, 165000);
> + }
> +
> + return max_tmds_clock;
> +}
> +
> static enum drm_mode_status
> hdmi_port_clock_valid(struct intel_hdmi *hdmi,
> - int clock, bool respect_dvi_limit)
> + int clock, bool respect_downstream_limits)
> {
> struct drm_device *dev = intel_hdmi_to_dev(hdmi);
>
> if (clock < 25000)
> return MODE_CLOCK_LOW;
> - if (clock > hdmi_port_clock_limit(hdmi, respect_dvi_limit))
> + if (clock > hdmi_port_clock_limit(hdmi, respect_downstream_limits))
> return MODE_CLOCK_HIGH;
>
> /* BXT DPLL can't generate 223-240 MHz */
> @@ -1312,7 +1328,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
> * within limits.
> */
> if (pipe_config->pipe_bpp > 8*3 && pipe_config->has_hdmi_sink &&
> - hdmi_port_clock_valid(intel_hdmi, clock_12bpc, false) == MODE_OK &&
> + hdmi_port_clock_valid(intel_hdmi, clock_12bpc, true) == MODE_OK &&
> hdmi_12bpc_possible(pipe_config)) {
> DRM_DEBUG_KMS("picking bpc to 12 for HDMI output\n");
> desired_bpp = 12*3;
> @@ -1352,10 +1368,41 @@ intel_hdmi_unset_edid(struct drm_connector *connector)
> intel_hdmi->has_audio = false;
> intel_hdmi->rgb_quant_range_selectable = false;
>
> + intel_hdmi->dp_dual_mode.max_tmds_clock = 0;
> +
> kfree(to_intel_connector(connector)->detect_edid);
> to_intel_connector(connector)->detect_edid = NULL;
> }
>
> +static void
> +intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector)
> +{
> + struct drm_i915_private *dev_priv = to_i915(connector->dev);
> + struct intel_hdmi *hdmi = intel_attached_hdmi(connector);
> + struct i2c_adapter *adapter =
> + intel_gmbus_get_adapter(dev_priv, hdmi->ddc_bus);
> + enum drm_dp_dual_mode_type type = drm_dp_dual_mode_detect(adapter);
> +
> + if (type == DRM_DP_DUAL_MODE_NONE)
> + return;
> +
> + /*
> + * Type 1 adaptors can be broken unfortunately, so let's
> + * not trust anything they say beyond the type identification.
> + */
> + if (type == DRM_DP_DUAL_MODE_TYPE2_DVI ||
> + type == DRM_DP_DUAL_MODE_TYPE2_HDMI) {
> + hdmi->dp_dual_mode.max_tmds_clock =
> + drm_dp_dual_mode_max_tmds_clock(adapter);
> + } else {
> + hdmi->dp_dual_mode.max_tmds_clock = 165000;
> + }
> +
> + DRM_DEBUG_KMS("DP dual mode adaptor (%s) detected (max TMDS clock: %d kHz)\n",
> + drm_dp_get_dual_mode_type_name(type),
> + hdmi->dp_dual_mode.max_tmds_clock);
> +}
> +
> static bool
> intel_hdmi_set_edid(struct drm_connector *connector, bool force)
> {
> @@ -1371,6 +1418,8 @@ intel_hdmi_set_edid(struct drm_connector *connector, bool force)
> intel_gmbus_get_adapter(dev_priv,
> intel_hdmi->ddc_bus));
>
> + intel_hdmi_dp_dual_mode_detect(connector);
> +
> intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
> }
>
> --
> 2.4.10
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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