Glitches deasserting the connector HPD line can lead to incorrectly detecting a disconnect event (a glitch asserting the line will only cause a redundant connect->disconnect transition). The source of such a glitch can be noise on the line or a 0.5ms-1ms MST IRQ_HPD pulse. TypeC ports in the DP-alt or TBT-alt mode filter out these glitches inernally, but for others the driver has to do this. Make it so by polling the HPD line on these connectors for 4 ms.
Signed-off-by: Imre Deak <[email protected]> --- drivers/gpu/drm/i915/display/intel_dp.c | 13 +++++++++++-- drivers/gpu/drm/i915/display/intel_tc.c | 9 +++++++++ drivers/gpu/drm/i915/display/intel_tc.h | 1 + 3 files changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index f04926d4aa80d..77ba6de6ba087 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5460,11 +5460,20 @@ bool intel_digital_port_connected_locked(struct intel_encoder *encoder) { struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); struct intel_digital_port *dig_port = enc_to_dig_port(encoder); + bool is_glitch_free = intel_tc_port_handles_hpd_glitches(dig_port); bool is_connected = false; intel_wakeref_t wakeref; - with_intel_display_power(dev_priv, POWER_DOMAIN_DISPLAY_CORE, wakeref) - is_connected = dig_port->connected(encoder); + with_intel_display_power(dev_priv, POWER_DOMAIN_DISPLAY_CORE, wakeref) { + unsigned long wait_expires = jiffies + msecs_to_jiffies_timeout(4); + + do { + is_connected = dig_port->connected(encoder); + if (is_connected || is_glitch_free) + break; + usleep_range(10, 30); + } while (time_before(jiffies, wait_expires)); + } return is_connected; } diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c index 80aed9e87927a..f34743e6eeed2 100644 --- a/drivers/gpu/drm/i915/display/intel_tc.c +++ b/drivers/gpu/drm/i915/display/intel_tc.c @@ -122,6 +122,15 @@ bool intel_tc_port_in_legacy_mode(struct intel_digital_port *dig_port) return intel_tc_port_in_mode(dig_port, TC_PORT_LEGACY); } +bool intel_tc_port_handles_hpd_glitches(struct intel_digital_port *dig_port) +{ + struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev); + enum phy phy = intel_port_to_phy(i915, dig_port->base.port); + struct intel_tc_port *tc = to_tc_port(dig_port); + + return intel_phy_is_tc(i915, phy) && !tc->legacy_port; +} + /* * The display power domains used for TC ports depending on the * platform and TC mode (legacy, DP-alt, TBT): diff --git a/drivers/gpu/drm/i915/display/intel_tc.h b/drivers/gpu/drm/i915/display/intel_tc.h index 936fa2daaa74a..26c4265368c1a 100644 --- a/drivers/gpu/drm/i915/display/intel_tc.h +++ b/drivers/gpu/drm/i915/display/intel_tc.h @@ -15,6 +15,7 @@ struct intel_encoder; bool intel_tc_port_in_tbt_alt_mode(struct intel_digital_port *dig_port); bool intel_tc_port_in_dp_alt_mode(struct intel_digital_port *dig_port); bool intel_tc_port_in_legacy_mode(struct intel_digital_port *dig_port); +bool intel_tc_port_handles_hpd_glitches(struct intel_digital_port *dig_port); bool intel_tc_port_connected(struct intel_encoder *encoder); -- 2.39.2
