drm/amd/display: Replace assert with error message in dp_retrieve_lttpr_cap()

[Why]
When assert in dp_retrieve_lttpr_cap() is hit, dmesg has traces like:

 RIP: 0010:dp_retrieve_lttpr_cap+0xcc/0x1a0 [amdgpu]
 Call Trace:
 <TASK>
  dp_retrieve_lttpr_cap+0xcc/0x1a0 [amdgpu]
  report_bug+0x1e8/0x240
  handle_bug+0x46/0x80
  link_detect+0x35/0x580 [amdgpu]

It happens when LTTPRs fail to increment dpcd repeater count.
We have a recovery action in place for such cases.
Assert is misleading, an indicative error in dmesg is more useful.

[How]
Remove ASSERT and use DC_LOG_ERROR instead.

Reviewed-by: Michael Strauss <michael.strauss@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index 46bb7a855bc218bf0f44cb1bf0d7ac38a9e3d9cb..c257e733044a64bb834b03e95d0df7249e2d7ded 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -1541,7 +1541,11 @@ enum dc_status dp_retrieve_lttpr_cap(struct dc_link *link)
         * Override count to 1 if we receive a known bad count (0 or an invalid value) */
        if ((link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
                        (dp_parse_lttpr_repeater_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt) == 0)) {
-               ASSERT(0);
+               /* If you see this message consistently, either the host platform has FIXED_VS flag
+                * incorrectly configured or the sink device is returning an invalid count.
+                */
+               DC_LOG_ERROR("lttpr_caps phy_repeater_cnt is 0x%x, forcing it to 0x80.",
+                            link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
                link->dpcd_caps.lttpr_caps.phy_repeater_cnt = 0x80;
                DC_LOG_DC("lttpr_caps forced phy_repeater_cnt = %d\n", link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
        }