[PATCH] drm/msm/dp: postpone irq_hpd event during connection pending state

From: Kuogee Hsieh
Date: Fri Dec 18 2020 - 12:54:47 EST


irq_hpd event can only be executed at connected state. Therefore
irq_hpd event should be postponed if it happened at connection
pending state. This patch also make sure both link rate and lane
are valid before start link training.

Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_display.c | 7 +++++++
drivers/gpu/drm/msm/dp/dp_panel.c | 12 +++++++++---
2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 6e971d5..3bc7ed2 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -693,6 +693,13 @@ static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
return 0;
}

+ if (state == ST_CONNECT_PENDING) {
+ /* wait until ST_CONNECTED */
+ dp_add_event(dp, EV_IRQ_HPD_INT, 0, 1); /* delay = 1 */
+ mutex_unlock(&dp->event_mutex);
+ return 0;
+ }
+
ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
if (ret == -ECONNRESET) { /* cable unplugged */
dp->core_initialized = false;
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 97dca3e..d1780bc 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -167,12 +167,18 @@ int dp_panel_read_sink_caps(struct dp_panel *dp_panel,
panel = container_of(dp_panel, struct dp_panel_private, dp_panel);

rc = dp_panel_read_dpcd(dp_panel);
+ if (rc) {
+ DRM_ERROR("read dpcd failed %d\n", rc);
+ return rc;
+ }
+
bw_code = drm_dp_link_rate_to_bw_code(dp_panel->link_info.rate);
- if (rc || !is_link_rate_valid(bw_code) ||
+ if (!is_link_rate_valid(bw_code) ||
!is_lane_count_valid(dp_panel->link_info.num_lanes) ||
(bw_code > dp_panel->max_bw_code)) {
- DRM_ERROR("read dpcd failed %d\n", rc);
- return rc;
+ DRM_ERROR("Illegal link rate=%d lane=%d\n", dp_panel->link_info.rate,
+ dp_panel->link_info.num_lanes);
+ return -EINVAL;
}

if (dp_panel->dfp_present) {
--
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