Hello Wenjing Liu,
The patch 1a206273c322: "drm/amd/display: refactor destructive verify
link cap sequence" from Jan 28, 2022, leads to the following Smatch
static checker warning:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:3248 dp_verify_link_cap()
error: uninitialized symbol 'status'.
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c
3192 static bool dp_verify_link_cap(
3193 struct dc_link *link,
3194 struct dc_link_settings *known_limit_link_setting,
3195 int *fail_count)
3196 {
3197 struct dc_link_settings cur_link_settings = {0};
3198 struct dc_link_settings initial_link_settings = *known_limit_link_setting;
3199 bool success = false;
3200 bool skip_video_pattern;
3201 enum clock_source_id dp_cs_id = get_clock_source_id(link);
3202 enum link_training_result status;
3203 union hpd_irq_data irq_data;
3204 struct link_resource link_res;
3205
3206 memset(&irq_data, 0, sizeof(irq_data));
3207 cur_link_settings = initial_link_settings;
3208
3209 /* Grant extended timeout request */
3210 if ((link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) && (link->dpcd_caps.lttpr_caps.max_ext_timeout > 0)) {
3211 uint8_t grant = link->dpcd_caps.lttpr_caps.max_ext_timeout & 0x80;
3212
3213 core_link_write_dpcd(link, DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT, &grant, sizeof(grant));
3214 }
3215
3216 do {
3217 if (!get_temp_dp_link_res(link, &link_res, &cur_link_settings))
3218 continue;
"status" is not set on this continure path.
3219
3220 skip_video_pattern = cur_link_settings.link_rate != LINK_RATE_LOW;
3221 dp_enable_link_phy(
3222 link,
3223 &link_res,
3224 link->connector_signal,
3225 dp_cs_id,
3226 &cur_link_settings);
3227
3228 status = dc_link_dp_perform_link_training(
3229 link,
3230 &link_res,
3231 &cur_link_settings,
3232 skip_video_pattern);
3233
3234 if (status == LINK_TRAINING_SUCCESS) {
3235 success = true;
3236 udelay(1000);
3237 if (read_hpd_rx_irq_data(link, &irq_data) == DC_OK &&
3238 hpd_rx_irq_check_link_loss_status(
3239 link,
3240 &irq_data))
3241 (*fail_count)++;
3242
3243 } else {
3244 (*fail_count)++;
3245 }
3246 dp_disable_link_phy(link, &link_res, link->connector_signal);
3247 } while (!success && decide_fallback_link_setting(link,
--> 3248 initial_link_settings, &cur_link_settings, status));
^^^^^^
Uninitialized variable
3249
3250 link->verified_link_cap = success ?
3251 cur_link_settings : fail_safe_link_settings;
3252 return success;
3253 }
regards,
dan carpenter
