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DS90UB941AS-Q1: Image quality issues(pixels are not clear at the edges)

Part Number: DS90UB941AS-Q1

Hi TI Team,

Continuing the below ticket,

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1060962/ds90ub941as-q1-image-quality-issues-on-the-display

we have one quality related issue on the images. When we render the images on the display, we could able to see the boarders are stretched.

Attaching the original image
Attaching the rendered image(processed image on the display)
And when we take the screenshot of the processed image using weston-screenshooter application. Image is clear and attaching the same screenshot
Is there any register configurations involves in this kind of edge cases ?
The register dump for serializer(DS90UB941As) and De-serializer(DS90UB948) is as follows:
root@dictgu:~# i2cdump -y -f 4 0x0c
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 58 00 00 01 ff ff 67 30 00 00    ?..?..X..?..g0..
10: 00 00 00 8f 00 00 fe 9e 7f 7f 01 00 80 00 01 00    ...?..?????.?.?.
20: 0b 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ?.%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 04 05 1e 00 00 00 00 00 00 00 00 00 00 00 00 8c    ???............?
50: 16 00 00 00 02 10 00 02 00 00 c9 03 07 06 44 5a    ?...??.?..????DZ
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80 00    ..............?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 38 00 00 64 40 00 00 00 00 02 ff 00    ..?.8..d@....?..
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 28 08 00 00 00 00 00 00 00 02 00 00    ..?.(?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
root@dictgu:~# i2cdump -y -f 4 0x2c
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 58 04 00 f0 fe 1e 00 18 00 00 00 00 00 00 00 00    X?.???.?........
10: 00 00 00 00 00 00 00 00 00 01 00 00 33 10 00 00    .........?..3?..
20: 90 00 40 20 08 00 83 84 11 00 00 00 00 00 00 00    ?.@ ?.???.......
30: 00 00 90 25 01 00 00 88 00 00 00 3f 20 e0 23 00    ..?%?..?...? ?#.
40: 43 03 03 00 60 88 00 00 0f 60 00 08 00 00 63 00    C??.`?..?`.?..c.
50: 03 10 00 01 80 00 00 00 00 7f 20 20 00 00 00 00    ??.??....?  ....
60: 00 00 00 00 10 00 00 00 00 00 00 00 00 00 00 00    ....?...........
70: 00 00 00 07 07 08 00 00 00 00 00 00 02 00 00 00    ...???......?...
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 8c 00 00 00 00 00 00 00 00 00 00 00 00 00    ..?.............
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 c0 00 00 00 00 00 00 00    ........?.......
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 5f 55 42 39 34 38 00 00 00 00 00 00 00 00 00 00    _UB948..........
root@dictgu:~#
please help us to solve this issue.
Thanks,
SAIKRISHNA
  • Hi Saikrishna, 

    With the glare in the picture showing the issue on display, its difficult to understand the issue here. Can you clarify the issue? 

    I would recommend starting with the DSI output packet first, can you use a DSI analyzer to verify the proper Hactive/Htotal timing values?

    Regards, 

    Logan

  • Hi Logan,

    As shown in the below picture(Highlighted with RED rectagular boxes), the pixels are not proper.

    We have sent a query to Display vendor as well for the timing parameters and waiting for their confirmation.

    Unfortunately, we do not have any DSI analyzer to verify the Hactive/Htotal values.

    Meantime, Can you please re-check on the register configuration and confirm us if any configuration is missed?

    For more details about the serializer/De-serializer configuration modes and other information, you can refer the attached tickets in this query itself.

    Thanks,

    SAIKRISHNA

  • Hi Saikrishna, 

    As shown in the below picture(Highlighted with RED rectagular boxes), the pixels are not proper.

    I'm still not completely sure what the issue is. You are saying the white to dark transition is incorrect? What is the over-all resolution of this panel? 

    I highly doubt this is a SerDes related problem, seems more like a timing issue or a panel issue.

    Is there any register configurations involves in this kind of edge cases ?

    No, this is not register configuration related. The only thing I can think that would impact something like this are the high-level panel config settings:

    Meantime, Can you please re-check on the register configuration and confirm us if any configuration is missed?

    Based on information that's currently know, I'm not sure we have enough to go off of to pin-point to a register config issue. I can take a look at the initialization script if you send that over.

    I would recommend to remove the end to end component to eliminate variables. Try doing PatGen from DES to display to see if this issue also occurs, as this could be panel related. (black/white checkerboard pattern would probably replicate this)

    Regards, 

    Logan