From: Michael Strauss <michael.stra...@amd.com>
[WHY]
i2c_read is called to differentiate passive DP->HDMI and DP->DVI-D dongles
The call is expected to fail in DVI-D case but pass in HDMI case
Some HDMI dongles have a chance to fail as well, causing misdetection as DVI-D
[HOW]
Retry i2c_read to ensure failed result is valid
Signed-off-by: Michael Strauss <michael.stra...@amd.com>
Reviewed-by: Tony Cheng <tony.ch...@amd.com>
Acked-by: Leo Li <sunpeng...@amd.com>
---
.../gpu/drm/amd/display/dc/core/dc_link_ddc.c | 24 ++++++++++++++-----
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
index 9a56f110bbd1..7f904d55c1bc 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
@@ -374,6 +374,7 @@ void dal_ddc_service_i2c_query_dp_dual_mode_adaptor(
enum display_dongle_type *dongle = &sink_cap->dongle_type;
uint8_t type2_dongle_buf[DP_ADAPTOR_TYPE2_SIZE];
bool is_type2_dongle = false;
+ int retry_count = 2;
struct dp_hdmi_dongle_signature_data *dongle_signature;
/* Assume we have no valid DP passive dongle connected */
@@ -386,13 +387,24 @@ void dal_ddc_service_i2c_query_dp_dual_mode_adaptor(
DP_HDMI_DONGLE_ADDRESS,
type2_dongle_buf,
sizeof(type2_dongle_buf))) {
- *dongle = DISPLAY_DONGLE_DP_DVI_DONGLE;
- sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_DVI_MAX_TMDS_CLK;
+ /* Passive HDMI dongles can sometimes fail here without
retrying*/
+ while (retry_count > 0) {
+ if (i2c_read(ddc,
+ DP_HDMI_DONGLE_ADDRESS,
+ type2_dongle_buf,
+ sizeof(type2_dongle_buf)))
+ break;
+ retry_count--;
+ }
+ if (retry_count == 0) {
+ *dongle = DISPLAY_DONGLE_DP_DVI_DONGLE;
+ sink_cap->max_hdmi_pixel_clock =
DP_ADAPTOR_DVI_MAX_TMDS_CLK;
- CONN_DATA_DETECT(ddc->link, type2_dongle_buf,
sizeof(type2_dongle_buf),
- "DP-DVI passive dongle %dMhz: ",
- DP_ADAPTOR_DVI_MAX_TMDS_CLK / 1000);
- return;
+ CONN_DATA_DETECT(ddc->link, type2_dongle_buf,
sizeof(type2_dongle_buf),
+ "DP-DVI passive dongle %dMhz: ",
+ DP_ADAPTOR_DVI_MAX_TMDS_CLK / 1000);
+ return;
+ }
}
/* Check if Type 2 dongle.*/
--
2.23.0
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