drm/i915: Check PSR setup time vs. vblank length
Bspec says:
"Restriction : SRD must not be enabled when the PSR Setup time from DPCD
00071h is greater than the time for vertical blank minus one line."
Let's check for that and disallow PSR if we exceed the limit.
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 68bd0bb..2b0d1ba 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -327,6 +327,9 @@
struct drm_i915_private *dev_priv = to_i915(dev);
struct drm_crtc *crtc = dig_port->base.base.crtc;
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+ const struct drm_display_mode *adjusted_mode =
+ &intel_crtc->config->base.adjusted_mode;
+ int psr_setup_time;
lockdep_assert_held(&dev_priv->psr.lock);
WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
@@ -365,11 +368,25 @@
}
if (IS_HASWELL(dev) &&
- intel_crtc->config->base.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE) {
+ adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE) {
DRM_DEBUG_KMS("PSR condition failed: Interlaced is Enabled\n");
return false;
}
+ psr_setup_time = drm_dp_psr_setup_time(intel_dp->psr_dpcd);
+ if (psr_setup_time < 0) {
+ DRM_DEBUG_KMS("PSR condition failed: Invalid PSR setup time (0x%02x)\n",
+ intel_dp->psr_dpcd[1]);
+ return false;
+ }
+
+ if (intel_usecs_to_scanlines(adjusted_mode, psr_setup_time) >
+ adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay - 1) {
+ DRM_DEBUG_KMS("PSR condition failed: PSR setup time (%d us) too long\n",
+ psr_setup_time);
+ return false;
+ }
+
dev_priv->psr.source_ok = true;
return true;
}