Re: [REGRESSION] Resolutions broken after "drm/msm: dsi: fix PLL init in bonded mode"

[Thorsten Leemhuis]

On 5/4/26 22:09, Mohit Dsor wrote:
> Sorry for the late reply. I am attaching clk_summary and reg_dump in
> working and non working case. Lilliput is just a normal display working
> with hdmi and has 720p as preferred mode. Yes, I was talking about RB3
> Gen2 only.

Neil, Dmitry, and Mohit: what's the status here? From the outside it
looks like this regression is still unfixed with nothing happening for
weeks now. Or has progress been made and I just missed it?

Ciao, Thorsten

> On Sun, Apr 26, 2026 at 4:14 AM Dmitry Baryshkov
> <dmitry.baryshkov@xxxxxxxxxxxxxxxx
> <mailto:dmitry.baryshkov@xxxxxxxxxxxxxxxx>> wrote:
> 
>     On Sun, Apr 26, 2026 at 03:38:49AM +0530, Mohit Dsor wrote:
>     > Hi Neil, all,
>     >
>     > We are seeing a regression after:
>     >
>     > drm/msm: dsi: fix PLL init in bonded mode
>     > https://lore.kernel.org/r/20251027-topic-sm8x50-fix-dsi-bonded-
>     v1-1-a477cd3f907d@xxxxxxxxxx <https://lore.kernel.org/r/20251027-
>     topic-sm8x50-fix-dsi-bonded-v1-1-a477cd3f907d@xxxxxxxxxx>
>     >
>     > Issue:
>     > - Resolutions are broken after this change. Like if we try to run
>     720p60 it will be 720p30.
>     >   Even though the byte_clk is set correctly, the bridge is
>     receiving half the byte clock.
>     >   Some divider is getting set which is causing the byte_clk to get
>     half, ultimately fps to
>     >   get half. Some other resolutions may or may not be broken
> 
>     Please provide necessary excerpts from /sys/kernel/debug/clk/clk_summary
>     for the working and for the broken cases. Also if there is a difference
>     in DSI PHY registers, please capture those (see
>     /sys/kernel/debug/dri/*/kms, provide necessary DSI PHY regs).
> 
>     > Reproduction:
>     > - Used QNX RB3Gen2 Core kit with lilliput display and lt9611uxc
>     dsi to hdmi bridge.
> 
>     What is lilliput? What is QNX RB3 Gen2? Is it the normal Thundercomm's
>     RB3 Gen2 or some other board sold with the same name?
> 
>     > - Run 720p60 usecase on hdmi with dsi to hdmi bridge.
>     >
>     > Expected behavior:
>     > - Display should support the expected resolutions correctly.
>     >
>     > Actual behavior:
>     > - No display on lilliput display.
>     >
>     > Additional details:
>     > - Reverting this change locally avoids the issue.
>     >
>     > Could you please take a look?
>     >
>     > Thanks,
>     > Mohit
> 
>     -- 
>     With best wishes
>     Dmitry
>