From: Dave Airlie <airlied@xxxxxxxxxx>
The DP1.2 spec has some bits for forced load sensing on VGA dongles,
however the apple dongle I have doesn't do DP 1.2 yet, so I dug into
its vendor specific area and found a register that seems to correspond
to load detected on the outputs.
The main reason I need this was at LCA this year the slide capture system
failed to provide EDID, but I realised OSX worked. Really need to add support
to nouveau, but hey i915 is a start.
The dongle also appears to use short IRQs to denote a plug/unplug event,
though something seems to be failing in reading back the dpcd values from it.
(also this is based on my MST work just because.)
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 29 +++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_drv.h | 1 +
include/drm/drm_dp_helper.h | 19 +++++++++++++++++++
3 files changed, 49 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c500f63..49afd7d 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3173,6 +3173,16 @@ intel_dp_probe_oui(struct intel_dp *intel_dp)
DRM_DEBUG_KMS("Branch OUI: %02hx%02hx%02hx\n",
buf[0], buf[1], buf[2]);
+ intel_dp->is_apple_vga = false;
+ if (drm_dp_branch_is_apple(buf)) {
+ u8 mybuf[8];
+ if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_BRANCH_OUI + 3, mybuf, 8)) {
+ if (drm_dp_apple_has_load_detect(mybuf)) {
+ DRM_DEBUG_KMS("detected Apple DP VGA dongle\n");
+ intel_dp->is_apple_vga = true;
+ }
+ }
+ }
edp_panel_vdd_off(intel_dp, false);
}
@@ -3404,6 +3414,21 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
if (drm_probe_ddc(&intel_dp->aux.ddc))
return connector_status_connected;
+ if (intel_dp->is_apple_vga) {
+ u8 detect_buf;
+ int ret;
+ ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_APPLE_LOAD_DETECT,
+ &detect_buf);
+
+ if (ret == 1) {
+ DRM_DEBUG_KMS("Apple VGA detect is 0x%x\n", detect_buf);
+ /* I suspect 4 == load, 8 == edid */
+ if (detect_buf)
+ return connector_status_connected;
+ else
+ return connector_status_disconnected;
+ }
+ }
/* Well we tried, say unknown for unreliable port types */
if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11) {
type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;
@@ -3854,6 +3879,10 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
* but for short hpds we should check it now
*/
intel_dp_check_link_status(intel_dp);
+
+ /* if we get a short hpd on apple vga - its a hotplug */
+ if (intel_dp->is_apple_vga)
+ return true;
}
}
return false;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1edb38a..23f767c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -549,6 +549,7 @@ struct intel_dp {
bool use_tps3;
bool can_mst; /* this port supports mst */
bool is_mst;
+ bool is_apple_vga;
int active_mst_links;
/* connector directly attached - won't be use for modeset in mst world */
struct intel_connector *attached_connector;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 517d6c1..c8ebd27 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -612,4 +612,23 @@ int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link);
int drm_dp_aux_register(struct drm_dp_aux *aux);
void drm_dp_aux_unregister(struct drm_dp_aux *aux);
+#define DP_APPLE_OUI 0x10fa
+
+#define DP_APPLE_LOAD_DETECT (DP_BRANCH_OUI + 12)
+
+static inline bool drm_dp_branch_is_apple(const u8 buf[3])
+{
+ if (buf[0] == ((DP_APPLE_OUI >> 16) & 0xff) &&
+ buf[1] == ((DP_APPLE_OUI >> 8) & 0xff) &&
+ buf[2] == ((DP_APPLE_OUI & 0xff)))
+ return true;
+ return false;
+}
+
+static inline bool drm_dp_apple_has_load_detect(const u8 buf[8])
+{
+ if (!memcmp((const char *)buf, "mVGAa", 5))
+ return true;
+ return false;
+}
#endif /* _DRM_DP_HELPER_H_ */
--
1.9.3
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