The causes of clock recovery and channel equalization failures are not explicitly printed in debug messages. Help debugging link training failures by printing why it failed.
Doing this in the driver would mean re-implementing some of the drm static functions that decode link status. Let's avoid that with these debug messages in drm.
Signed-off-by: Dhinakaran Pandiyan dhinakaran.pandiyan@intel.com --- drivers/gpu/drm/drm_dp_helper.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 091053e..d763b57 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -64,12 +64,16 @@ bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
lane_align = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED); - if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0) + if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0) { + DRM_DEBUG_KMS("Inter-lane alignment not done\n"); return false; + } for (lane = 0; lane < lane_count; lane++) { lane_status = dp_get_lane_status(link_status, lane); - if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS) + if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS) { + DRM_DEBUG_KMS("Channel equalization not done for lane %d\n", lane); return false; + } } return true; } @@ -83,8 +87,10 @@ bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
for (lane = 0; lane < lane_count; lane++) { lane_status = dp_get_lane_status(link_status, lane); - if ((lane_status & DP_LANE_CR_DONE) == 0) + if ((lane_status & DP_LANE_CR_DONE) == 0) { + DRM_DEBUG_KMS("Clock recovery not done for lane %d\n", lane); return false; + } } return true; }