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drm/amd/display: disable lttpr for invalid lttpr caps.
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1-Read lttpr caps in 5-bytes
2-Parse caps
3-Validate caps and set lttpr_mode
4-Use hw default timeout when lttpr is disabled.

Signed-off-by: abdoulaye berthe <abdoulaye.berthe@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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abdoulaye berthe authored and Alex Deucher committed Nov 13, 2019
1 parent 9bffd08 commit 61aa7a6
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Showing 3 changed files with 49 additions and 58 deletions.
90 changes: 46 additions & 44 deletions drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1172,15 +1172,15 @@ static void configure_lttpr_mode(struct dc_link *link)
uint8_t repeater_cnt;
uint32_t aux_interval_address;
uint8_t repeater_id;
enum lttpr_mode repeater_mode = phy_repeater_mode_transparent;
uint8_t repeater_mode = DP_PHY_REPEATER_MODE_TRANSPARENT;

core_link_write_dpcd(link,
DP_PHY_REPEATER_MODE,
(uint8_t *)&repeater_mode,
sizeof(repeater_mode));

if (!link->is_lttpr_mode_transparent) {
repeater_mode = phy_repeater_mode_non_transparent;
repeater_mode = DP_PHY_REPEATER_MODE_NON_TRANSPARENT;
core_link_write_dpcd(link,
DP_PHY_REPEATER_MODE,
(uint8_t *)&repeater_mode,
Expand Down Expand Up @@ -2964,7 +2964,11 @@ static void dp_wa_power_up_0010FA(struct dc_link *link, uint8_t *dpcd_data,

static bool retrieve_link_cap(struct dc_link *link)
{
uint8_t dpcd_data[DP_ADAPTER_CAP - DP_DPCD_REV + 1];
/* DP_ADAPTER_CAP - DP_DPCD_REV + 1 == 16 and also DP_DSC_BITS_PER_PIXEL_INC - DP_DSC_SUPPORT + 1 == 16,
* which means size 16 will be good for both of those DPCD register block reads
*/
uint8_t dpcd_data[16];
uint8_t lttpr_dpcd_data[6];

/*Only need to read 1 byte starting from DP_DPRX_FEATURE_ENUMERATION_LIST.
*/
Expand All @@ -2977,7 +2981,6 @@ static bool retrieve_link_cap(struct dc_link *link)
union dp_downstream_port_present ds_port = { 0 };
enum dc_status status = DC_ERROR_UNEXPECTED;
uint32_t read_dpcd_retry_cnt = 3;
uint32_t prev_timeout_val;
int i;
struct dp_sink_hw_fw_revision dp_hw_fw_revision;

Expand All @@ -2988,12 +2991,12 @@ static bool retrieve_link_cap(struct dc_link *link)
link->is_lttpr_mode_transparent = true;

if (ext_timeout_support) {
prev_timeout_val =
dc_link_aux_configure_timeout(link->ddc,
LINK_AUX_DEFAULT_EXTENDED_TIMEOUT_PERIOD);
dc_link_aux_configure_timeout(link->ddc,
LINK_AUX_DEFAULT_EXTENDED_TIMEOUT_PERIOD);
}

memset(dpcd_data, '\0', sizeof(dpcd_data));
memset(lttpr_dpcd_data, '\0', sizeof(lttpr_dpcd_data));
memset(&down_strm_port_count,
'\0', sizeof(union down_stream_port_count));
memset(&edp_config_cap, '\0',
Expand Down Expand Up @@ -3026,47 +3029,46 @@ static bool retrieve_link_cap(struct dc_link *link)
}

if (ext_timeout_support) {

status = core_link_read_dpcd(
link,
DP_PHY_REPEATER_CNT,
&link->dpcd_caps.lttpr_caps.phy_repeater_cnt,
sizeof(link->dpcd_caps.lttpr_caps.phy_repeater_cnt));

if (link->dpcd_caps.lttpr_caps.phy_repeater_cnt > 0) {

DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
lttpr_dpcd_data,
sizeof(lttpr_dpcd_data));

link->dpcd_caps.lttpr_caps.revision.raw =
lttpr_dpcd_data[DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV -
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];

link->dpcd_caps.lttpr_caps.max_link_rate =
lttpr_dpcd_data[DP_MAX_LINK_RATE_PHY_REPEATER -
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];

link->dpcd_caps.lttpr_caps.phy_repeater_cnt =
lttpr_dpcd_data[DP_PHY_REPEATER_CNT -
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];

link->dpcd_caps.lttpr_caps.max_lane_count =
lttpr_dpcd_data[DP_MAX_LANE_COUNT_PHY_REPEATER -
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];

link->dpcd_caps.lttpr_caps.mode =
lttpr_dpcd_data[DP_PHY_REPEATER_MODE -
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];

link->dpcd_caps.lttpr_caps.max_ext_timeout =
lttpr_dpcd_data[DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT -
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];

if (link->dpcd_caps.lttpr_caps.phy_repeater_cnt > 0 &&
link->dpcd_caps.lttpr_caps.max_lane_count > 0 &&
link->dpcd_caps.lttpr_caps.max_lane_count <= 4 &&
link->dpcd_caps.lttpr_caps.revision.raw >= 0x14) {
link->is_lttpr_mode_transparent = false;

status = core_link_read_dpcd(
link,
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
(uint8_t *)&link->dpcd_caps.lttpr_caps.revision,
sizeof(link->dpcd_caps.lttpr_caps.revision));

status = core_link_read_dpcd(
link,
DP_MAX_LINK_RATE_PHY_REPEATER,
&link->dpcd_caps.lttpr_caps.max_link_rate,
sizeof(link->dpcd_caps.lttpr_caps.max_link_rate));

status = core_link_read_dpcd(
link,
DP_PHY_REPEATER_MODE,
(uint8_t *)&link->dpcd_caps.lttpr_caps.mode,
sizeof(link->dpcd_caps.lttpr_caps.mode));

status = core_link_read_dpcd(
link,
DP_MAX_LANE_COUNT_PHY_REPEATER,
&link->dpcd_caps.lttpr_caps.max_lane_count,
sizeof(link->dpcd_caps.lttpr_caps.max_lane_count));

status = core_link_read_dpcd(
link,
DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT,
&link->dpcd_caps.lttpr_caps.max_ext_timeout,
sizeof(link->dpcd_caps.lttpr_caps.max_ext_timeout));
} else {
dc_link_aux_configure_timeout(link->ddc, prev_timeout_val);
/*No lttpr reset timeout to its default value*/
link->is_lttpr_mode_transparent = true;
dc_link_aux_configure_timeout(link->ddc, LINK_AUX_DEFAULT_TIMEOUT_PERIOD);
}
}

Expand Down
15 changes: 2 additions & 13 deletions drivers/gpu/drm/amd/display/dc/dc_types.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -420,20 +420,9 @@ enum link_training_offset {
LTTPR_PHY_REPEATER8 = 8
};

enum lttpr_mode {
phy_repeater_mode_transparent = 0x55,
phy_repeater_mode_non_transparent = 0xAA
};

enum lttpr_rev {
lttpr_rev_unknown = 0x0,
lttpr_rev_14 = 0x14,
lttpr_rev_max = 0x20
};

struct dc_lttpr_caps {
enum lttpr_rev revision;
enum lttpr_mode mode;
union dpcd_rev revision;
uint8_t mode;
uint8_t max_lane_count;
uint8_t max_link_rate;
uint8_t phy_repeater_cnt;
Expand Down
2 changes: 1 addition & 1 deletion drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@
#define LINK_TRAINING_ATTEMPTS 4
#define LINK_TRAINING_RETRY_DELAY 50 /* ms */
#define LINK_AUX_DEFAULT_EXTENDED_TIMEOUT_PERIOD 3200 /*us*/
#define LINK_AUX_DEFAULT_TIMEOUT_PERIOD 400 /*us*/
#define LINK_AUX_DEFAULT_TIMEOUT_PERIOD 552 /*us*/

struct dc_link;
struct dc_stream_state;
Expand Down

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