Some dongle set both link lane and rate to 0 during dpcd receiver
capability read if there is no monitor attache to this dongle.
Therefore return fail to prevent driver from trying to populate
monitor further.
Changes in V2:
-- split this patch into two. Move postpone irq_handle into next patch
-- add Fixes tag
Fixes: 78f94fbb6122 ("drm/msm/dp: fix connect/disconnect handled at irq_hpd")
Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_panel.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
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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a Linux Foundation Collaborative Project
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