Dear TI engineer, hello! We are working on lighting DLP2010+DLPC3430+DLPA2000. The equipment is currently lit and the pictures are drawn normally, but after we put the machine for a period of time, dots of pictures will appear. We use fans to dissipate heat. Disappeared, we don’t know if it is caused by heat or my DSI is configured incorrectly. Do you have a similar case that can be solved?
Thank you very much for your reply. We tried to increase the clock frequency from 86MHZ to 98MHZ. The problem still exists. We used the same machine to test under the same brightness, room temperature and black picture. About three minutes later, the screen started to appear. Very slight red dots. At about 5 minutes, the screen started to be mixed with white dots and red dots. At this time, the phenomenon was obvious. At about 8 minutes, the screen began to appear large areas of white dots, almost full The entire screen. 86MHZ and 98MHZ phenomenon are the same, so I feel that increasing the frequency has no effect, and when I am in the pattern mode, that is, the control register 0x0B, this situation will also occur. The time when the light spot appears is almost the same as the situation with DSI.
dsi-panel-wo-kernel-dtsi.txt
&mdss_mdp {
dsi_wo_dlp_wvga_video: qcom,mdss_dsi_wo_dlp_wvga_video {
qcom,mdss-dsi-panel-name = "Wo dlp wvga video mode dsi panel";
qcom,mdss-dsi-panel-type = "dsi_video_mode";
qcom,dsi-ctrl-num = <0>;
qcom,dsi-phy-num = <0>;
qcom,mdss-dsi-virtual-channel-id = <0>;
qcom,mdss-dsi-stream = <0>;
qcom,mdss-dsi-bpp = <24>;
qcom,mdss-dsi-underflow-color = <0xff>;
qcom,mdss-dsi-border-color = <0>;
qcom,mdss-dsi-traffic-mode = "non_burst_sync_event";
qcom,mdss-dsi-bllp-eof-power-mode;
qcom,mdss-dsi-bllp-power-mode;
qcom,mdss-dsi-force-clock-lane-hs;
qcom,mdss-dsi-tx-eot-append;
qcom,mdss-dsi-lane-0-state;
qcom,mdss-dsi-lane-1-state;
qcom,mdss-dsi-lane-2-state;
qcom,mdss-dsi-lane-3-state;
qcom,mdss-dsi-dma-trigger = "trigger_sw";
qcom,mdss-dsi-mdp-trigger = "none";
qcom,mdss-dsi-bl-pmic-control-type = "none";
qcom,mdss-dsi-reset-sequence = <1 10>, <0 10>, <1 10>;
qcom,mdss-dsi-display-timings {
timing@0 {
qcom,mdss-dsi-panel-width = <854>;
qcom,mdss-dsi-panel-height = <480>;
qcom,mdss-dsi-h-front-porch = <38>;
qcom,mdss-dsi-h-back-porch = <24>;
qcom,mdss-dsi-h-pulse-width = <24>;
qcom,mdss-dsi-h-sync-skew = <0>;
qcom,mdss-dsi-v-back-porch = <14>;
qcom,mdss-dsi-v-front-porch = <8>;
qcom,mdss-dsi-v-pulse-width = <7>;
qcom,mdss-dsi-h-left-border = <0>;
qcom,mdss-dsi-h-right-border = <0>;
qcom,mdss-dsi-v-top-border = <0>;
qcom,mdss-dsi-v-bottom-border = <0>;
qcom,mdss-dsi-h-sync-pulse = <0>;
qcom,mdss-dsi-panel-framerate = <60>;
//qcom,mdss-dsi-on-command = [];
//qcom,mdss-dsi-off-command = [];
//qcom,mdss-dsi-on-command-state = "dsi_lp_mode";
//qcom,mdss-dsi-off-command-state = "dsi_hs_mode";
};
};
};
};
Here we share some test result and analysis .
Precondition:
Q1: If we increase the DSI clock, can the bright dot issue be observed as well?
A1: We tried to set it to 98MHz and the bright dot is observed.
Steps: Set different DSI clock.
|
|
After 3min |
After 5min |
After 8min |
|
86MHz |
Weak red dots are observed. |
Obvious white and red dots are observed, but not all over the display area. They are mainly on the left side.(Q1_T5) |
The white dots are all over the area.(Q1_T8) |
|
98MHz |
Weak red dots are observed. |
Obvious white and red dots are observed, but not all over the display area. They are mainly on the left side.(Q1_T5) |
The white dots are all over the area.(Q1_T8) |
Q2: Turn off DSI output, set the register 0x0B（Write Test Pattern Select（W 0xD7 0x01)（W 0x05 0x01）(W 0x0B 0x80 0x00 )）. No image input and it only shows the black pattern.
A2: The bright dot is observed after 8 mins.
|
After 3min |
After 5min(Q2_T5) |
After 8min(Q2_T8) |
|
Weak red dots are observed. |
Obvious white and red dots are observed, but not all over the display area. They are mainly on the left side. |
The white dots are all over the area. |
Q3: Turn off DSI output. Set the display to DisplayImageCurtain mode (W 36 16 01）.
A3: The bright dot is observed after 8 mins.
|
After 3min |
After 5min(Q3_T5) |
After 8min(Q3_T8) |
|
Weak red dots are observed. |
Obvious white and red dots are observed, but not all over the display area. They are mainly on the left side. |
The white dots are all over the area. |
Based on the result above, we know that the bright dots are observed even without DSI signal. The time when it is observed is the same with or without the DSI signal.
The bright dots should be related to the heat, not the DSI settings.
