1080p60 video flash of DSI output

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

Hi,
We are currently debugging the DSI output of our TX2 Board (2xHDMI and 1xDSI). And the dts is as follows(dsi output is 1080P 60Hz) :
dsi.dtsi (10.6 KB)

Like the discussion: 1080p60 video refresh of DSI output can 't reach 60HZ
We are also using ADV7535 connected on the DSI-0 output which is to achieve the function of dsi transfer to hdmi.
We also encounter the screen flash problem. (Please see the video attached https://drive.google.com/file/d/1bxWYKklKe3LNN82cd4xb4TRNQ56AJEjH/view) If we left the desktop image still, everything seems to be ok. If we open the file Explorer or Setup Page of Ubuntu, the dsi screen begin flashing. (Brightness is not stable, sometime high and sometime low. The HDMI output is correct)
Our TX2 is already in the max power mode and SDK is R28.4.
Have any suggestion for this ?

3

Hi,

Sorry, I am not sure about the usecase when ADV7535 is connected. Is the backlight still give stable voltage when error happens?

4

Hi,
The adv7535 has not backlight control. Our tx2’s backlight is not connected to adv7535.

5

Hi,
1.We do not use the PWM Backlight Control since ADV7535 do not have backlight control pin. May this cause the flash problem ?
2.We check the DSI Spec. MIPI-DSI Protocol could transmit the Display Command Set.
The command : set_gamma_curve might influence the brightness. Is it possible the cause of the problem ?
Is there any way to disable the Display Command Set of the DSI protocol?

6

Sorry that we cannot tell the cause since ADV7535 is getting involved.

The display command set should be defined in your dsi DTS files.

8

debug1.7z (93.8 KB)
Hi,
I uploaded two pictures.
In the two pictures the channel 2 (green) is vsync and the channel 3 (blue) is hsync.
The picture of hdmi.png is the normal hdmi output.
The picture of dsi_hdmi.png is the dsi to hdmi output. (by pass only)
In the dsi_hdmi.png. The length of hsync output (marked with red box) seems strange (vfront-porch + hsync-len + vback-porch).
Can I setup the dsi make the output normal ?

12

Just to double confirm that issue have been resolved by your debugging, and we can close this issue, right?

13

Yes, thanks.

14

Good to know issue resolved by your debugging. Thanks for the confirmation.