From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
DP dongles may signal downstream HPD via short HPD pulses. Setting the
sink to DPMS off apparently kills the downstream HPD (at least on my
DP->VGA dongle), so skip the DPMS off for such dongles when we turn
off the port.
v2: Deal with DDI as well by moving the check into
intel_dp_sink_dpms() (Dhinakaran)
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Cc: Pablo <pablodebiase@xxxxxxxxxxxxx>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103472
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99114
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index aa75f55eeb61..59169a4dc9d3 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2505,6 +2505,21 @@ static void ironlake_edp_pll_off(struct intel_dp *intel_dp)
udelay(200);
}
+static bool downstream_hpd_needs_d0(struct intel_dp *intel_dp)
+{
+ /*
+ * DPCD 1.2+ should support BRANCH_DEVICE_CTRL, and thus
+ * be capable of signalling downstream hpd with a long pulse.
+ * Whether or not that means D3 is safe to use is not clear,
+ * but let's assume so until proven otherwise.
+ *
+ * FIXME should really check all downstream ports...
+ */
+ return intel_dp->dpcd[DP_DPCD_REV] == 0x11 &&
+ intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT &&
+ intel_dp->downstream_ports[0] & DP_DS_PORT_HPD;
+}
+
/* If the sink supports it, try to set the power state appropriately */
void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
{
@@ -2515,6 +2530,9 @@ void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
return;
if (mode != DRM_MODE_DPMS_ON) {
+ if (downstream_hpd_needs_d0(intel_dp))
+ return;
+
ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
DP_SET_POWER_D3);
} else {
--
2.13.6
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