DSI driver difference between kernel 5.4.47 vs 4.14.98

[jemish_1990]

Hi All,

• We are working product based on IMX8MQ.
• We want to use LCD panel  (via eLCDIF + MIPI DSI) which works at 6.5 Mhz pixel clock.
• First we tried to make this LCD work with 4.14.98  because we are already using this kernel in our product but it doesn't work.
• So we tried with kernel 5.4.47 and we managed to make LCD panel work with this kernel version.
• Now if take same panel driver in 4.14.98 kernel it's not working. That means for sure there are some significant changes between kernel 4.14.98 DSI driver/eLCDIF driver vs drivers of 5.4.47.
• I tried on my own to find out changes and try to implement in 4.14.98 kernel but it doesn't help.
• Can any from NXP point out significant changes (commits, paches) related to DSI or eLCDIF driver so that I can make LCD panel work with 4.14.98 also.

Please note that at this stage we can't use 5.4.47 kernel in our product as it product with 4.14.98 is already market and we want to add support of new LCD panel on top of that.

Thanks,

Jemish

[igorpadykov]

Hi Jemish

one can look at below link (in particular kopera patches)

https://community.nxp.com/t5/i-MX-Processors/Display-pixel-clock-limitation-to-74-25-MHz/m-p/914038

Best regards
igor

[jemish_1990]

Hi Igor,

After applying commits provided by NXP we are able to configure desired pixel clock but still issue that we don't see Data on LCD panel.

One thing we observe that in kernel 5.4.47 we see LP and HS sections in DSI clock while in kernel 4.14.98 we only see clock and no such LP and HS sections.

Do you have any suggestion for that?

Thanks,

Jemish

[jemish_1990]

Hi Igor,

This issue is resolve now. We have panel working! Thanks for you support!

You can mark this thread as close.

Thanks,

Jemish