Hi team,
The customer encountered some problems when using 941-926, and hoped that BU could help answer and analyze them.
1、On the customer's SOC side, the dtb parameters are as follows:
dsi0: currently only use DSI0, DSI1 is not connected.
864x480p@60
Clock: <31500000>; //31.5M
hactive = <864>;
vactive = <480>;
hback-porch = <60>;
hfront-porch = <60>;
hsync-len = <16>;
vback-porch = <8>;
vfront-porch = <35>;
vsync-len = <2>;
Problem: There is no signal from VS and HS on the 926 side, and there is no output on the screen.
2、
In the pattern mode of 941, if the following command is used, the external clock should be used according to the manual,
i2cset -f -y 3 0xc 0x65 0x08
i2cset -f -y 3 0xc 0x64 0x05
Must add:
i2cset -f -y 3 0x0c 0x40 0x04
i2cset -f -y 3 0x0c 0x41 0x20
i2cset -f -y 3 0x0c 0x42 0x6f
For these three sentences, the color bar can be output normally.
However, if the customer does not use the Pattern mode and uses the video picture sent from the SOC side, the 926 side does not respond, even if the customer runs the above three lines of commands. Therefore, the customer's initial judgment is whether there is a problem with the timing on the SOC side?
3、There are two very strange phenomena:
3.1 It is reasonable to say that we need to disable the 941 register for 941 register configuration, and finally enable it. However, the actual result is that once we do "i2cset -f -y 3 0x0c 0x01 0x02,
"i2cset -f -y 3 0x0c 0x01 0x4,"i2cset -f -y 3 0x0c 0x01 0x08 # DSI disable", any sentence, the whole function will be abnormal, including Pattern mode.
3.2 Another phenomenon is that according to theoretical calculations, our clock frequency is 31.5M, 4Lanes, single Port DSI0. The theoretical value of TSKIP_CNT below should be 0x02. However, the time situation is that the default 0x3A must be kept. If you set If 0x02 is set, the pattern function will also fail.
