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drm/i915/dp: Read DPRX for all long HPD pulses

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The TBT DP tunnel BW request logic in the Thunderbolt Connection Manager
depends on the GFX driver reading out the sink's DPRX capabilities in
response to a long HPD pulse. Since in i915 this read-out can be blocked
by another connector's/encoder's hotplug event handling (which is
serialized by drm_mode_config::connection_mutex), do a dummy DPRX read-out
in the encoder's HPD pulse handler (which is not blocked by other
encoders).

Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240220211841.448846-21-imre.deak@intel.com
This commit is contained in:
Imre Deak 2024-02-20 23:18:40 +02:00
parent fb687904aa
commit a32f3a9541
1 changed files with 12 additions and 0 deletions
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12
drivers/gpu/drm/i915/display/intel_dp.c
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@ -6165,6 +6165,7 @@ intel_dp_hpd_pulse(struct intel_digital_port *dig_port, bool long_hpd)
{
struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
struct intel_dp *intel_dp = &dig_port->dp;
u8 dpcd[DP_RECEIVER_CAP_SIZE];
if (dig_port->base.type == INTEL_OUTPUT_EDP &&
(long_hpd || !intel_pps_have_panel_power_or_vdd(intel_dp))) {
@ -6187,6 +6188,17 @@ intel_dp_hpd_pulse(struct intel_digital_port *dig_port, bool long_hpd)
dig_port->base.base.name,
long_hpd ? "long" : "short");
/*
* TBT DP tunnels require the GFX driver to read out the DPRX caps in
* response to long HPD pulses. The DP hotplug handler does that,
* however the hotplug handler may be blocked by another
* connector's/encoder's hotplug handler. Since the TBT CM may not
* complete the DP tunnel BW request for the latter connector/encoder
* waiting for this encoder's DPRX read, perform a dummy read here.
*/
if (long_hpd)
intel_dp_read_dprx_caps(intel_dp, dpcd);
if (long_hpd) {
intel_dp->reset_link_params = true;
return IRQ_NONE;