Re: [PATCH 2/6] drm/i915/psr: Tie PSR2 support to Y coordinate requirement in intel_psr_init_dpcd()

Rodrigo Vivi
2018-03-16T00:36:02Z

On Wed, Mar 14, 2018 at 03:36:13PM -0700, José Roberto de Souza wrote:
> Move to only one place the sink requirements that the actual driver
> needs to enable PSR2.
>
> Also intel_psr2_config_valid() is called every time the crtc config
> is computed, wasting some time every time it was checking for
> Y coordinate requirement.
>
> This allow us to nuke y_cord_support and some of VSC setup code that
> was handling a scenario that would never happen(PSR2 without Y
> coordinate).
>
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 1 -
> drivers/gpu/drm/i915/intel_psr.c | 55 ++++++++++++++++++++--------------------
> 2 files changed, 28 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 8a584273f897..d4bc8d18f56c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -603,7 +603,6 @@ struct i915_psr {
> unsigned busy_frontbuffer_bits;
> bool psr2_support;
> bool link_standby;
> - bool y_cord_support;
> bool colorimetry_support;
> bool alpm;
> bool has_hw_tracking;
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 9811f5f0bc75..62d97d5576d1 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -93,7 +93,7 @@ static void psr_aux_io_power_put(struct intel_dp *intel_dp)
> intel_display_power_put(dev_priv, psr_aux_domain(intel_dp));
> }
>
> -static bool intel_dp_get_y_cord_status(struct intel_dp *intel_dp)
> +static bool intel_dp_get_y_coord_required(struct intel_dp *intel_dp)
> {
> uint8_t psr_caps = 0;
>
> @@ -137,22 +137,38 @@ void intel_psr_init_dpcd(struct intel_dp *intel_dp)
>
> if (INTEL_GEN(dev_priv) >= 9 &&
> (intel_dp->psr_dpcd[0] & DP_PSR2_IS_SUPPORTED)) {
> - uint8_t frame_sync_cap;
> + uint8_t frame_sync_cap, y_coord_req;
>
> dev_priv->psr.sink_support = true;
> +
> + /* PSR2 needs frame sync to do selective updates */
> if (drm_dp_dpcd_readb(&intel_dp->aux,
> DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
> &frame_sync_cap) != 1)
> frame_sync_cap = 0;
> frame_sync_cap = (frame_sync_cap & DP_AUX_FRAME_SYNC_CAP);
> - /* PSR2 needs frame sync as well */
> - dev_priv->psr.psr2_support = frame_sync_cap;
> - DRM_DEBUG_KMS("PSR2 %s on sink",
> - dev_priv->psr.psr2_support ? "supported" : "not supported");
> +
> + /*
> + * FIXME: Enable PSR2 only for y-coordinate PSR2 panels
> + * After GTC implementation, remove this restriction.

I believe we should remove the FIXME and just comment out that non y-coordinate
would need GTC that we currently don't implement.

later if we change our minds and decided to add that support we revisit here
but without a FIXME poluting code for something we don't plan to support for now.

> + *
> + * All panels that supports PSR version 3 that is

PSRv3? is there really something formal about that?

> + * PSR2 + Y-coordinate support can handle Y coordinates in VSC
> + * but we are only sure that it is going to be used when
> + * required by the panel. This way panel is capable to do
> + * selective update even without a valid aux frame sync.
> + */
> + y_coord_req = intel_dp_get_y_coord_required(intel_dp);
> +
> + dev_priv->psr.psr2_support = frame_sync_cap && y_coord_req;
> + if (dev_priv->psr.psr2_support)
> + DRM_DEBUG_KMS("PSR2 supported on sink\n");
> + else
> + DRM_DEBUG_KMS("PSR2 not supported on sink"
> + "(frame sync: %d Y-coord required: %d)\n",
> + frame_sync_cap, y_coord_req);
>
> if (dev_priv->psr.psr2_support) {
> - dev_priv->psr.y_cord_support =
> - intel_dp_get_y_cord_status(intel_dp);
> dev_priv->psr.colorimetry_support =
> intel_dp_get_colorimetry_status(intel_dp);
> dev_priv->psr.alpm =
> @@ -198,16 +214,12 @@ static void hsw_psr_setup_vsc(struct intel_dp *intel_dp,
> memset(&psr_vsc, 0, sizeof(psr_vsc));
> psr_vsc.sdp_header.HB0 = 0;
> psr_vsc.sdp_header.HB1 = 0x7;
> - if (dev_priv->psr.colorimetry_support &&
> - dev_priv->psr.y_cord_support) {
> + if (dev_priv->psr.colorimetry_support) {
> psr_vsc.sdp_header.HB2 = 0x5;
> psr_vsc.sdp_header.HB3 = 0x13;
> - } else if (dev_priv->psr.y_cord_support) {
> + } else {
> psr_vsc.sdp_header.HB2 = 0x4;
> psr_vsc.sdp_header.HB3 = 0xe;
> - } else {
> - psr_vsc.sdp_header.HB2 = 0x3;
> - psr_vsc.sdp_header.HB3 = 0xc;
> }
> } else {
> /* Prepare VSC packet as per EDP 1.3 spec, Table 3.10 */
> @@ -478,15 +490,6 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
> return false;
> }
>
> - /*
> - * FIXME:enable psr2 only for y-cordinate psr2 panels
> - * After gtc implementation , remove this restriction.
> - */
> - if (!dev_priv->psr.y_cord_support) {
> - DRM_DEBUG_KMS("PSR2 not enabled, panel does not support Y coordinate\n");
> - return false;
> - }
> -
> return true;
> }
>
> @@ -586,14 +589,12 @@ static void hsw_psr_enable_source(struct intel_dp *intel_dp,
> struct drm_device *dev = dig_port->base.base.dev;
> struct drm_i915_private *dev_priv = to_i915(dev);
> enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> - u32 chicken;
>
> psr_aux_io_power_get(intel_dp);
>
> if (dev_priv->psr.psr2_support) {
> - chicken = PSR2_VSC_ENABLE_PROG_HEADER;
> - if (dev_priv->psr.y_cord_support)
> - chicken |= PSR2_ADD_VERTICAL_LINE_COUNT;
> + u32 chicken = PSR2_VSC_ENABLE_PROG_HEADER
> + | PSR2_ADD_VERTICAL_LINE_COUNT;
> I915_WRITE(CHICKEN_TRANS(cpu_transcoder), chicken);
>
> I915_WRITE(EDP_PSR_DEBUG,
> --
> 2.16.2